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International Edition 



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OCTOBER 1989 

ISSUE #349 

USA $2.95 

CAN $3.95 

A WGE Publication 



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Home-brew: 

Standardize radio-"f j n JC connsciion 
Packs! for psnniss on iris SX-S4 
Data/voics/band switch ooa 
Jrnproye you/TNC's ODD 
Packs! racks! squelch 



e views: 

DfiSiJ PC; Packs! Adaptor 



GfU\P53 53 Xb niodanj 



rutorials: 

Your first packet station! 

All about networking protocols 



i o 




7482 



08725 ■ 









(COM 



IC-2400 UHF/VHF Mobile 
IC-2500 UHF/12GHZ Mob 




Stack today's rapidly expanding VHF7UHF 
action in your favor with the most advanced 
design vet easv-tooperate FM dual banders 
on the road: ICftM s IC-2400 2-meter/440MHz 
or IC-2500 440MHz/L2 GHz. 

Their overlapping band ranges are great 
for present use and future expansions, and 
their wide array of impressive features 
make your auto a douobmobile winner! 

WIDEBAND COVERAGE. 

The O400's range of 138474MHz RX/ 
140-lSOMHz TX and 440-450MHz RX/TX 
includes NOAA weather reception plus 
liberal overlap for MARS/CAP operation. 
The innovative IC-2500 receives and 
transmits 44O450MH2 and 1240-130QMH2. 

HIGH POWER RADIOS! 

The IC-2400 delivers 45 watts output 
on two-meters, 35 watts on 440MHz. The 
IC-2500 features 35 watts on 440MHz 



10 watts on L2GHz + Both 
units include selectable 
low power for working 
local stations. 

FULL DUPLEX OPERATION. 

Both transceivers transmit on one band 
while simultaneously receiving on another. 
Both radios feature independent offsets for 
each band- Its like having two separate radios 
in one! Perfect for true telephone-style auto- 
patching with a modern crossband repeater! 

SIMULTANEOUS DUAL RAND 
RECEPTION. 

Monitor both bands on the internal speaker 
or add external speakers- Each band features 
separate volume and squelch controls. 

40 MEMORIES. 

Twenty per band. Store frequencies, PL 
tones and TX offsets for super<onvenient 
mi 



IC-2500 monitor the action. A sheer VHF/ 
UHF delight! 

Additional features include: Priority 
Watch, Monitor one channel's activity 
while operating on another frequency Two 
Call Channels. One on each band for 
auick, single access to your favorite repeater. 
A Repeater Input Monitor Switch for 
rapid checks of t X offset and evaluation of 
direct range. Plus, an Optional Beeper 
silently monitors any selected frequency or 
repeater for calls with pur preselected 
CTCSS subaudible tone. 

Double your bands with ICOMs new 
IC-2400 or IC*25QG mobiles! 

COM Amenca, he, 2380-1 iffli Ave, N£, Mevue. WA 99004 
Customer Service Hotline (206) 454-7619 

3150 Premier Drive, Suite 1 2fi, Irving. TX 75063 
177? Phoenix Parkway, Suite 201, Mania, GA 30349 
ICOM CANADA. A Division of SCGM America, Inc., 
3071 - US Road, Unit 9, Richmond, B.C. V6X 2T4 Canada 

AM sated specifications are subjed to change without notice or oWigafton. 
Al ICOM radios significantly exceed FCC regulations limiting spurious 
3400 25O07&S 




o 



MEMORY SCANNING. 

You set the limits and select/lockout 
preferred memories. ICOMs IC-2400 and 



ICOM 

First In Communications 



CIRCLE 354 ON READER SERVICE CARD 



NO OTHER FULL DUPLEX PATCH OR 
REPEATER CONTROLLER GIVES YOU 

SO MUCH FOR SO LITTLE 



FULL DUPLEX AUTOPATCH 
USING DUAL BAND 
RADIOS... 

Most people are within radio range of 

their base station 90% of the time. 
Why not install an 8200 and enjoy your 
own private full duplex mobile 
telephone system? Only 3 

connections are required. The 8200 
provides both full duplex and half 
duplex operation, 

(Inquire about Private Patch V for 
simplex operation. Operates in 
enhanced sampling or VOX 
modes... user selectable.) 

ADVANCED AUTOPATCH 
FEATURES.,. 

The 8200 incorporates many features 

which are simply not available in any 
other product For example,.. 

90 Phone Number Auto Dialer: The 
8200 will store (in non-volatile memory) 
90 phone numbers which can be dialed 
with abbreviated two digit key codes. 
The auto dialer is programmable over 
the air or with the built-in keyboard. 

Last Number Redial: Redialing the last 
number called is reduced to a single 
digit (plus access code). 

Hookflash: Operates call waiting etc. 
Simply press * three times. Only CSI 
has it. 

Call Progress Tone Detection: Busy 
signals and second dial tones are 
detected and cause automatic 
disconnect. Ample time is allowed for 
dialing second dial tones when 
required. 

Powerful Toll Protection: One to four 
digit sequences can be restricted. For 
example, you could lock out P 1, 976 
and 911. Additionally, digit counting 
will prevent dialing more than 10 digits, 
A separate 2 to 6 digit toll override 
code allows making toll calls when 
desired. Re-arm is automatic. 

Dial Access Remote Base: The 8200 
can be accessed and controlled from 
any telephone. Call up and drop into 
the system from your desk phone at 
lunch hour! 




ttJLLOUFCU 



CflKlmtta/ taf f f LoniMtl •* 



* • 



.f %_: 



Rinaout Selective Calling: Ordinary 
calls can be received using ringout 
(reverse patch} and mobiles can be 
selectively called using regenerated 
DTMF 

Optional AN I access codes: This 
option will allow up to 50 separate 

(remotely programmable) 1 to 6 digit 
access codes. A call can only be 
disconnected with the code that 
initiated the call. Thus eliminating 
sabotage disconnects. 



AN ADVANCED REPEATER 
CONTROLLER,,, 

The 8200 is a powerful repeater 
building block and is perfect for all 
private and club systems. 

The 8200 contains everything 
necessary to convert any receiver and 
transmitter into a powerful repeater. 
Only one connection to the receiver 
and two to the transmitter are required. 

Menu style programming is 
accomplished with the built in keyboard 
and display. The user can select a 3 
digit repeater up/down code, CW ID 
message, CW ID interval, hang time, 
activity timer time, and you can even 
select any Morse character as a 
courtesy beep!! 

An optional plug-in CTCSS board 
converts the 8200 to private use. The 
incoming CTCSS is filtered out and 
replaced with fully regen rated tone. 32 
tones are dip switch selectable. 



STANDARD FEATURES... 

• Line in use detection 

• 90 number auto dialer 

• Redial 

• Hookflash 

• User programmable CW ID 

• Regenerated tone/pulse dialing 

• Selectable activity, timeout and hang 
time timers 

• 3 digit repeater on/off code 

• Two remotely programmable 1-6 digit 

autopatch connect codes. (Regular 
and Toll Override) 

• Powerful toll protection 

• Remotely controllable relay (relay 

optional) 

• Ringout (reverse patch) 

• Busy channel ringout inhibit 

• Ring counting 

• Auto answer 

• Telephone remote base 

• DTMF-DTMF selective calling 

• Courtesy beep (any Morse character) 

• Automatic busy signal and dial tone 

disconnect 

• MOV lightning protectors 

• Non-volatile memory 
And MUCH more! 







Connect Systems Inc. 

2064 Eastman Ave. #113 

Ventura, CA 93003 

Phone (805) 642-7184 

FAX (805) 642-7271 



CIRCLE 12 ON READER SERVICE CARD 



• 



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Food for thought. 

Our new Universal Tone Encoder tends its versatility 
to all tastes. The menu includes all CTCSS, as well 
as Burst Tones, Touch Tones, and Test Tones. No 
counter or test equipment required to set frequency - 
just dial it in. While traveling, use it on your Amateur 
transceiver to access tone operated systems, or in 
your service van to check out your customers" re- 
peaters; also, as a piece of test equipment to modulate 
your Service Monitor or signal generator. It can even 
operate off an internal nine volt battery, and is available 
for one day delivery, backed by our one year warranty. 



• All tones in Group A an J Group B are included. 

• Output level flat to within l.5db over entire range selected. 

• Separate level adjust pots and output connections for each 
tone Group* 

• Immune to RF 

• Powered by 6*30vde, unregulated at 8 ma, 

• Low impedance, low distortion, adjustable Mnewave 
output. 5v peak to-peak 

• Instant start-up. 

• Off position for no tone output* 

■ Reverse polarity protection built-in. 



Group A 








67.0 XZ 


91.5 ZZ 


M8.8 2B 


156.7 5A 


71.9 XA 


94 8 ZA 


123,0 3Z 


162.2 SB 


74 4 WA 


97.4 ZB 


127.3 3 A 


167,9 6Z 


77.0 XB 


100.0 IZ 


131.8 3B 


173.8 6A 


79.7 SP 


103.5 IA 


136 5 4Z 


179 9 68 


82.5 YZ 


107.2 LB 


141. 34A 


186.2 7Z 


85.4 YA 


] 10,9 2Z 


146 2 4B 


192.8 7 A 


88.5 YB 


1 14.8 2A 


151,452 


203.5 Ml 



• Frequency accuracy, ± . I Hz maximum - 40°C to + 85°C 

• Frequencies to 250 Hz available on special order 

• Continuous tone 



Group 8 






TEST TONES: 


TOUCH TONES: 


BURST TONES 


600 


697 1209 


1600 1850 2150 2400 


1000 


770 1136 


1650 1900 2200 2450 


1500 


852 1477 


1700 L950 2250 2500 


2175 


941 1633 


1750 2000 2300 2550 


2H0S 




1 800 2100 2350 



• Frequency accuracy, ± 1 Hz maximum - 40°C lo + 85°C 

• Tone length approximately 300 ms. May be lengthened, 
shortened or eliminated by changing value of resistor 

Model TE-64 $79.95 




COMMUNICATIONS SPECIALISTS 

426 West Taft Avenue, Orange, California 92667 
(800) 854-0547/ California; (714) 998-3021 




READER SERVICE CARD 



QRM 



Editorial Of f ic es 

WGE Center 

Hancock NH 03449 

phone: &Q3 525-4201 

Advertising Offices 

WGE Center 

Hancock NH G3449 

phone: &OG-225-50B3 

Circulation Offices 

WGE Center 

Hancock NH 03449 

phone : 603-525-4201 



Manuscripts 
Contributions in the form of 
manuscripts with drawings and J 
or photographs are welcome end 
will be considered for possible publi- 
cation. We can assume no responsi- 
bility for loss or damage to any 
material. Please enclose a stamped, 
self-addressed envelope with each 
submission. Payment for the use of 
any unsolicited material will be 
made upon publication. A premium 
will be paid for accepted articles that 
have been submitted electronically 
(CompuServe ppn 70310,775 or 
MCI Mail "WGEPUB" or GEnie ad- 
dress "73MAG") or on disk as an 
IB Incompatible ASCII file. You can 
also contact us at I he 73 BBS at 
(603) 525-4438, 300 Or 1200 baud, 8 
data bits, no parity, one stop bit. All 
contributions should be directed to 
the 73 editorial offices. "How to 
Write for 73" guidelines are avail- 
able upon request- US citizens must 
include their social security number 
with submitted manuscripts. 

73 Amateur Radio (fSSN 0889- 
5309) is published monthly by WGE 
Publishing 1 Inc., WGE Center, 
Forest Road, Hancock, New Hamp- 
shire 03449 Entire contents %1989 
by WGE Publishing, Inc. No part of 
this publication may be reproduced 
without written permission from ihe 
publisher, For Subscription Ser- 
vices write 73 Amateur Radio. PO 
Box 58066, Boulder, CO B0322- 
8866, or call 1-80G-2BS-038B. In CO 
call 1-303-447-9330- The subscrip- 
tion rate is; one year $24,97; two 
years 139,97. Additional postage for 
Canada is $7.00 and for other for- 
eign countries, $19,00 surface and 
537.00 airmail per year. All foreign 
orders must be accompanied by 
payment is US funds. Second class 
postage paid at Hancock, New 
Hampshire and at additional mailing 
offices. Canadian second ciass mail 
registration number 9566. Microfilm 
Edition— University Microfilm, Ann 
Arbor, Ml 48106 Postmaster: send 
address changes to 73 Amateur 
Radio, PO Box 58866. Boulder, CO 
80322-8866, 

Contract: 

Even a glimpse at this constitutes 
a legal binding contract between 
you and the Publisher under which 
you are required to do everything 
within your power to determine 
when someone new has been li- 
censed in your area. You are then 
req u i red to take a p hoto of this unfor- 
tunate, prelerably with his/her 
Elmer, note Ihe calls involved, and 
send this to: Novice Identification 
Project, 73 Magazine, Forest Rd. 
Hancock, NH 03449. 



OCTOBER 1989 




AMATEUR 
RADIO 



Issue # 349 



TABLE OF CONTENTS 



WB6RQN 



FEATURES 

14 Setting Up a Packet Radio Station 

Read this for the info the how-to books left out! . , 

28 Digital Dreams 

The future of packet radio has arrived^ * N3EUA 

30 TNC PPM without the PC 

Give your older TNC personal mailbox capability with just a few keystrokes WB6WKB 

36 Packet Radio in Japan 

Bits of info on packet in the land of the Rising Sun. 

48 Packet Radio and Hi-Tech Nomadics 

How packet radio fits in with the world's highest-tech bicycle, . 

54 TexNet Packet- Switching Network 

Check out this highly effective low-overhead packet network. . . 

60 Amateur Packet Networking 

Going beyond keyboard-to-keyboard QSOs 

65 DX Dynasty Awards 

The Dynasty grows ... ,-..«.#.*'•• ..,.♦* 

68 TCP/IP for the Macintosh 

Merging this powerful networking system with a user-friendly micro! . . , .•.;*, ♦ * « WASDZP 

70 Vertical Antennas at HF— Part II 

More surprising facts about HF verticals, , ; . .*_., ,,,....., W I rV 



+ + # ■ ■« 



m * * -fa + hi* 



.,,..,, WAILBP 

N4RVE 

WD5IVD 

WB6RQN 

WB2DIN and 73 Staff 



+ h * r 9 



HOME-BREW 

13 Packet Racket Lip Zipper 

Automatic rig speaker silencer for packet operation * 

24 My SX-64 Runs Digicom! 

Run this popular low-cost packet interface on C-64's portable brother 

31 Put Your IC-22S on Packet 

Dust it off and dedicate it to 2m packet! . . 

32 K AM Box 
Switch mode and band in an instant > 

34 One-Chip RS-232 for the C-64 

Quick 'n easy level converter , 

40 Standardizing the Radio/TNC Interface 

Get up and running quickly with any rig/TNC combo. , * ♦ . . - WB6RQN 

50 improve Your TNC's DCD Circuit 

For a faster and smarter DCD ♦ * * ... . «»,..... - +■..,*.*.**_*■, ,«•.•'•••-...*., -< N7CL 

80 HF Packet Tuning Aid 

Hear your way to dead-on tuning. . - W610J 

84 The Quickchanger 

This makes mixed -mode /band operation a breeze ■ ■ ■ ■ KA3M] 



. .,.KBlUM 
. , . KA9ELV 
. , , . KE4PC 
t ,, . , N4AQG 
. ..KB0CDQ 



■ ■ * * 



REVIEWS 

20 DRSI PC* Packet Adaptor 

Packet interface on a PC expansion card* ,.,,*, 
42 GRAPES 56 Kbps Modem 

Transfer large program files in a flash on packet! 
59 DX Helper 

DX software for the Macintosh *.*......, 

99 Flodraw 

Simple schematic drawing on your PC 

DEPARTMENTS 



V * # * 



y f r + I- P 



. WB6RQN 

,..,.♦« KA9Q 
. .WB8EHS 
, WB9CWE 



FEEDBACK... 
FEEDBACK! 

lis like being there— right here 
in uuroffice&f How? Jusi take 
advantage of our FEEDBACK 
caxd on page 17. You'll notice 
a Feedback number at the begin- 
ning, of each article and 
column. We'd like you to rate 
what jou read io that we earn 
prim wtafl types of thing* you 
like best. And then we will draw 
one Feedback card each moutii 
for a free subscription to 73 . 



82 New Products 

103 Propagation 

11 QRX 

94 73 International 

90 Special Events 

98 Tech Tips 

92 Updates 

6 Welcome Newcomers 



88 Ad index 
102 Barter 'N'Buy 
100 Dealer Directory 

17 Feedback 

83 Ham Help 

17 Ham Profiles 

88 Index: 10 89 

92 Letters 
8 Never Say Die 

10 GHz 1 Megabit per second packet station, designed 
by Bdale N3EUA and Glenn N6GN. See page 28 for 
more on this system. Cover by Alice Scofield. 




"JS" VU2JX, a happy DXpeditJoner to 
the ■ Laccadives. Read about the trip on 
page 96, 



73 Amateur Radio * October, 1989 3 






MFJ, Bencher and Curtis team up to bring you America's most popular 
keyer in a compact package for smooth easy CW 




MFJ-422B 



The besl of all CW worlds - a deluxe MFJ Keyer using 3 Curtis 8044ABM chip in a 
compact package that fits right on the Bencher ram toe paddle! 

This MFJ Keyer is small in size but big in features. You get iambic keying, adjustable 
weight and tone and front panel volume and speed controls (8-50 WPM) T dot dash 
memories, speaker, sidetone and push button selection of automatic or semi-automatic/ 
tune modes. It's also totally RF proof and has ultra reliable solid state outputs that key 
both tube and solid state rigs. Use 9 V battery or 110 VAC with MFJ-1 305 t 

The keyer mounts on a Bencher paddle to form a small {4 1/8 x 2 5/8 x 57? inches) 
attractive combination that is a pleasure lo lock at and use. 

America's favorite paddle, the Bench, has adjustable gold-plated silver contacts, lucite 
paddles, chrome plated brass, and a heavy sleei base with non-skid feet. 
$4 OQ95 You can buy just the keyer assembly, MFJ 422BX, lor only $79.95 to mount on your 
™ » Bencher paddle. 





Artificial RF Ground 

MFJ 931 

$7ft»a 

You can 
create an 
artificial RF 

ground and eliminate RF "bites", 
feedback, TVI and flFI when you let the 
MFJ 931 resonate a random length of 
wire and turn it into a tuned counter 
poise. MFJ 931 also lets you electrically 
place 1 far away RF ground directly at 
your rig no matter how far away it »s 
-by tuning out the reactance of your 
ground connection wire. V/v&Vvt? in. 

Antenna Bridge ™*g 

How you can quickly 
optimize your antenna for 
peak performance with this 
portable, totally self- 
contained antenna bridge, 

No other equipment 
needed take it to your 
antenna site. Determine if 
your antenna is too long or 
too short, measure its 
resonant frequency and 
antenna resistance to 500 
ohms. It's the easiest, most 
convenient way to determine antenna 
performance. Built-in resistance bridge, 
null meter, tunable oscillator-driver 
(1,8-30 MHz). Use 9 V battery or 110 
VAC wifh AC adapter. 

Super Active Antenna 

'World Radio TV Handbook* says 
MFJ-1 Q|24 is "a first rate easy to operate 
active antenna ,.. quiet ... excellent 
dynamfc range ... good gain ... very low 
noise factor... broad frequency coverage 
excitant choice." 

it outdoors away from electrical 

maximum signal, minimum noise 

!* covers 50 KHz to 30 Mhz 

Receive* strong, clear signals 

ilrom all over the world. 20 dB 

attenuator, pin control. CW LED 

I Switch two receivers and aux, 

or active antenna 6x23x5 in. 

Remote unit has 54 inch whip, 

Ii^*mmmm 50 ft. coax and 
^-flnrj connector, 3x2x4 
.*«*- P in. 12VDCor 
-— T— fl 1 1 VAC with 

MFJ 1024 *1 29" MFJ-1 31 2. 



MFJ Coax Antenna Switches 








* 



*7 




*34 gS WFJ-170: *21 * 5 MFJ 1702 *50" MFJ-17D4 

Select any of several antennas horn your operating desk with these MFJ 
Coax Switches. They feature mounting holes and automatic grounding of 
unused terminals. They come with MFJ's one year unconditional guarantee. 
MFJ-1701, $34.95. Six position antenna switch SO 239 connectors 50 75 
ohm loads. 2 KW PEP, 1 KW Cw, fitack aluminum 1 0x3x1 V2 inch cabinet, 
MFJ 1702, $21.95. 2 positions. Cavity construction, 2.5 KW PEP t 1 KW CW. 
Insertion loss below Z dB. 50 dB isolation at 450 MHz. 50 ohm, 3x2x2 in. 
MFJ-1 704, $59.95. 4 position Cavity Switch with Lightening/Surge protection 
device. Center Ground position. 2.5 KW PEP, 1 KW CW. Extremely low SWR. 
Isolation better than 50 dB 500 MHz. Negligible loss. SO ohm. 6V*x4V*x1 V* in. 



ii 



Dry" Dummy Loads for HF/VHF/UHF 






Mou 

noise f 
MFJ-1 




New 



MFJ-260 ■ MFJ-262 W* MFJ 264 

*28 05 G9^*69 95 H^^^ M09 95 

MFJ has a full line of dummy loads to suit your needs. Use a dummy load 
for tuning to reduce needless (and illegal) 0RM and save your finals, 
MFJ-260, $28,95. Air cooled, non-inductive 50 ohm resistor. SO 239 
connector. Handles 300 watts. Run full load lor 30 seconds, derating curve to 
5 minutes. SWR less than 1.3:1 to 30 MHz, 1.5:1 30 60 MHz. 2V2x2Vzx7 in, 
MFJ-262,$69.95. Handles 1 KW. SWR less than 1.5:1 to 30 MHz, 3x3x13 in. 
MFJ 264. $109.95. Versatile UHF/VHF/HF 1.5 KW Dry Dummy Load. An MFJ 
first. Gives you low SWR to 650 MHz + usable to 750 MHz. You can run 100 
watts for 10 minutes, 1500 watts tor 10 seconds. SWR is 1.1:1 to 30 MHz, 
below 1,3:1 to 650 MHz. 3x3x7 inches. SO 239 connector 

. MFJ-1 286 Gray Line DX Advantage 

t** *29 0S MFJ-1266 SnaQ r3re 0X t0f 0rity * 29 95 " The MFJ * 1286 

is a computerized DXing tool that predicts DX 
propagation. Even the casual DXer can work rare 
DX by knowing when conditions are best tor DX. 
The Gray Line is the day/night divider tine where 
the most amazing DX happens every day. Now 
you'll know exactly when to take advantage of it 
Gives detailed world map. Shows Gray Line for 
any date/time* UTC in 24 user chosen QTHs. time 
zones and more. IBM compatible. Any graphics. 

MFJ's Speaker/Mies ■»«» 

For Kenwood, loom, Yaesu, Santec '24" 

MFJ's compact Speaker/Mies let you carry your HT on your 
bell and never have to remove it 10 monitor calls or talk. 

You get a wide range speaker and lirstrate electret mic 
etement for superb audio on bath transmit and receive, 

Earphone jack, handy lapetfpocket clip, PTT, lightweight 
retractable cord. Gray. One year unconditional guarantee. 

MFJ 2fl4 fits Icom, Yaesu, Santec. MFJ-286 fits Kenwood. 






• One year unconditional guarantee • 30 day 
money back guarantee (less s/h) on orders from 
MFJ • Add $5.00 each $/h * Ftee catalog 




MFJ ... making quality affordable 



12/24 Hour LCD Clocks 



■hw Win* m mPMu 



*1 9 95 MFJ-1QflB S 9" HFJ-107B 

Huge 5/8 inch bold LCD digits let you 
see the correct time from anywhere in 
your shack. Choose from the dual clock 
that has separate UTOIocal time display 
or the single 24 hour ham clock. 

Mounted in a brushed aluminum 
frame. Easy to set The world's most 
popular ham clocks tor accurate logs 
MFJ 108B 4V2Xlx2; MFJ 107B 2V«1x2. 

Lighted Cross/Needle 
SWR/Wattmeter $|g»s 

MFJ Cross- 
Needle SWR/ 
Wattmeter 
shows you 
SWR, forward 

and reflected power in 3 ranges /20D/ 
2000 watts forward /50/500 reflected). 
Push button range selection. 1 .8-30 MHz. 

Mechanical zero adjust for movement. 
SO 239 connectors. Light requires 12 
VDC or 110 VAC with MFJ-1 31 2 t $9,95, 

Deluxe Code Practice 
n** Oscillator 

MFJ557 

*24 95 

MFJ-557 Deluxe Code Practice 
Oscillator has a Morse key and oscillator 
unit mounted together on a heavy steel 
base so it stays put on your table. Also 
portable because it runs on a 9 volt 
battery (not included) or an AC adapter 
that plugs into the side, 

Earphone jack tor private practice 
Tone and volume controls for a wide 
range of sound. Speaker. The key has 
adjustable contacts and can be hooked 
to your transmitter. Sturdy. BVzx2Vix3*A 
in. One year unconditional guarantee. 

MFJ AC Voltage Monitor 

*1 9 95 MFJ-850 Ne* 

Prevent damage to rig, 
computer or other gear. 
Monitor AC line voltage for 
potentially damaging surge/ 1 
brown out conditions on 
2 color expanded 95-1 35 volt scale. 

Plugs into any AC outlet- 2% 
accuracy. 2V«2V4x1Vj inches. 

MFJ ENTERPRISES, INC. 

P,0, Box 494, Mississippi State. MS 39762 
{601 ) 323 5869; TELEX: 534590 MFJSTKV 
Nearest Dealer or Orders only: 600-547-1800 

CIRCLE 24 ON READER SERVICE CARD 





MFJ's new ham license upgrade Theory Tutor 

get your ham license for only $29.95 with MFJ Theory Tutor! This fun new software 
practically guarantees you § tlpass the theory part of any FCC ham license exam! 



MF J Theory Tutor 



Cjf*r*h1 lM hy OM Safturil 



PO Box HSH 
Mississippi St«tt, MS 

Pr«5 any k*y to continue --> 
Presi H for Help* 



Here is (he opening screen of MFJ's 
Theory Tutor -- a friendly, fun and 
effective computerized teacher that 
gives you the edge you need to pass 
your next FCC ham license exam. A 
great gift for the budding Novice! 







i jitten «t| «ff jf tier *i$-ii c»«ftfP4i*tL 

mi tir lint tin tk» [b itbr 
ft prtii** ttti *** #f tk ipus 

rwewfratti is tw 4M$if#' & 
I fitfent #i1* *si *f III iNU 






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I s 

: 

j 



An easy-to-use on-line calculator is 
ready to help you when needed. 
Calculators are allowed in FCC 
testing sessions. To the right is the 
bar graph display that keeps up with 
your score as you go along. 




You can change the screen colors 
with the Utilities menu. This lets you 
easily select the colors that make the 
MFJ Theory Tutor most pleasing on 
your computer screen. 




ft faiklt £i*frmi9a httim 

I 51 iff U luisw^.wd^ft* te*it*f, 



AH 1 esf d i ag ra n is and fig u res a re fnc t tided j or color g rap h ics i n MFJ *s 
Theory Tutor. One key switches you between the question and the 
diagram on the left. After you have studied the picture, you can go back 
and answer the question. These easy-to-read computer graphics are the 
same ones used an the tests* 




ffi ScEmF!? «5j« 



Here is the detailed score bar graph 
screen that you can bring up during 
a study session or at the end. H glues 
you a graphic display of your score in 
each exam category. 



• Concentrate on any specific area or on the entire FCC question pool 

• Take sample tests or print written tests 

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CIRCLE 86 ON READER SERVICE CARD 



Number 1 on your Feedback card 



Welcome, 
Newcomers! 



[Words in bold face are those you will 
encounter frequently in the features in 
this issue , and in packet radio in general* 
. , .Eds J 



Welcome to the 73 Special Packet Issue, in 
which you will find nearly 40 pages devoted 
to the fastest growing aspect in amateur ra- 
dio! What is packet radio? Like radioteletype 
(RTTY), amateur teleprinting over radio 
(AMTOR), and even Morse code (CW), 
packet is digital communications rather than 
voice communications, With packet radio, 
you can transmit any form of information that 
can be represented as digital (on/off or dis- 
crete values) information. A typical packet 
station contains only three items— a 
transceiver, a computer or terminal, and an 
interfacing device, usually called a Terminal 
Node Controller (TNC) or data controller, 
which links the rig and computer. 

Features Unique to Packet 

Packet radio works by collecting informa- 
tion and then transmitting it in bursts or pack- 
ets. Each packet contains a special error de- 
tecting code that allows the receiver to 
determine whether or not the packet was 
damaged or changed in transit. Damaged 
packets are discarded by the receiver, and the 
sender then retransmits another copy of the 
packet. Each packet contains a source and 
destination callsign so that only the intended 
recipient will process the packet. This allows 
several packet "conversations*' to go on at 
the same time on the same frequency. 

The procedure followed by both the sender 
and receiver to ensure the transmission of 
information is called a protocol. The most 
popular protocol used in amateur packet ra- 
dio is called AX*25 because it is based on the 
worldwide computer networking protocol 

Networking— Packet Radio's 
Newest Feature 

Networking is a way of connecting com- 
puters together so that they can communicate 
fficiently, To simplify understanding of net- 
working, its features are broken down into 



e 



component levels or layers, each with its own 
general function. 

Why use layers? Well, imagine that you are 
trying to understand how a car works. You 
probably will study individually the parts 
of the car — the engine, the transmission, 
the suspension, the electrical system, and 
so on. When you understand the function 
and features of each, you can more easily 
understand how it all fits together to form a 
car. Understanding the layers of a computer 
network works the same way; if you under- 
stand the functions of each layer, you can 
better understand the function of the entire 
network. 

Much study went into defining the compo- 
nent parts of a network. The result is a 
scheme composed of seven components or 
layers. 

These layers are named physical, link, 
network, transport, session, presentation, 
and application. The physical layer de- 
scribes the way to move the raw data from 
one point to another and includes descriptions 
of such items as voltages, connectors, signal 
frequency, and the like. The physical layer in 
amateur packet radio typically uses narrow- 
band frequency modulation (NBFM) radios 
to carry the signal. The digital data, the bi- 
nary ones and zeros, are fed into a device 
called a modem, which converts the digital 
information into a signal that can be sent over 
the radio. The modem on the receiving end 
converts the signal back into the original digi- 
tal signal for processing. The AX. 25 link 
layer ensures that any errors that occur dur- 
ing the transfer process are corrected. 

Packet communications works best when 
the physical link is good (very few errors) and 
AX .25 doesn't have much to do. Several arti- 
cles in this issue deal with ways to physically 
transmit information faster, farther, and with 
fewer errors. 

See the article "Amateur Radio Network- 
ing" in this issue for a fuller description of 
the network layers. 

Until recently, packet radio was pretty 
much limited to point-to-point communica- 
tions. There really wasn't a network layer to 
route the data to a distant station via interme- 
diary stations. Neither was there a good 



transport layer to ensure that the message, 
when it reached the final destination, was 
accurate. There was no session layer to keep 
multiple activities {for example, a keyboard- 
to-screen chat and a file transfer) separated, 
and no presentation layer to hide the differ- 
ences between computer systems. 

Times have certainly changed. Now there 
is the Transmission Control Protocol/Inter- 
net Protocol (TCP/IP), the RATS Open Sys- 
tem Environment (ROSE), TexNet, and 
NET/ROM. Each of these networking sys- 
tems offers a different mechanism for moving 
packet information long distances. 

Once there is a way of moving digital infor- 
mation long distances reliably, there is a de- 
sire to use that resource. Something that uses 
the network is called an application. The 
most common application (and up until now 
just about the only application) in packet ra- 
dio is the bulletin board system (BBS). A 
BBS is a computer program that lets you use 
packet radio to send and receive electronic 
mail and bulletin messages. New applications 
are beginning to appear that permit someone 
to query about another ham, send or receive a 
computer program, or perhaps let your com- 
puter use the resources of a remote computer 
system, 

Higher speeds, more reliable links, and 
better networking protocols will give rise to 
new applications. The 56,000 bit per second 
modem described by Phil Karn in this issue 
will make the computer-to-computer link 
comfortable. The 1,500,000 bit per second 
microwave packer system shown on the cover 
will make digital voice and digital amateur 
television possible. The bottom line is that 
packet radio is going to eventually affect ev- 
ery aspect of amateur radio, from chasing DX 
to providing better public and emergency 
communications service. 

Now is the time for you to get involved with 
amateur packet radio. You can use it right 
now as an everyday aspect of your communi- 
cations and you can get involved in experi- 
mentation and advancing the state-of-the-art. 
Either way, you will be challenged and de- 
lighted by this diverse and interesting facet of 
the exciting hobby of amateur radio. 

...deWB6RQN 



6 73 Amateur Radio • OctobGr, 1989 



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Never sa y die 



Wayne Green W2NSD/1 




EMP Revisited 

Seven years ago the FCC's De- 
fense Commissioner, Mimi Daw- 
son, with the support of Chairman 
Mark Fowler and Senator Goldwa- 
ter, formed the Long Range Plan- 
ning Committee (LRPC) with four 
National Industry Advisory Com- 
mittees (NIAC) to assist it. The LR- 
PC was made up of top executives 
in the communications industry,, 
brought together to formulate an 
overall plan for emergency com- 
munications for our country. 

The first step was to see what 
had been done in the past to cope 
with emergencies — what systems 
were available and how they had 
worked. The next step was to took 
cfosely at ail communications sys- 
tems and their rote in helping us 
cope with future emergencies. 
Emergencies encompassed ev- 
erything from local problems due 
to accidents, fires and floods, to 
regional emergencies doe to 
earthquakes, right on up to the 
ultimate emergency: an atomic 
attack. 

The LRPC soon had to face one 
fundamental fact: Only the ama- 
teur radio service had the po- 
tential for providing the needed 
communications. The military de- 
pended almost entirely on com- 



mercial telephone lines for their 
communications (95%)— and the 
first thing which seems to go out In 
any emergency is the telephone. 
Indeed, it was this which put the 
Alaskan military bases out of com- 
munications with the Pentagon for 
almost a week following the 
Alaskan earthquake. Their only 
communications were via hastily 
set up amateur radio networks. 

The LRPC and the FCC then 
faced an extremely serious prob- 
lem. If the only dependable emer- 
gency communications system 
which could tie together police, 
fire, towns, road crews, two-way 
services such as trucks, taxis and 
doctors, television remote units, 
CB T CAP, MARS T broadcast radio 
and TV, and so on, was amateur 
radio, then we were going to need 
a substantial growth and modern- 
ization of this service. The traffic 
volumes estimated were several 
orders of magnitude beyond the 
capability of our present voice or 
CW communications systems, 
These volumes could only be han- 
dled by high speed automated 
digital communications, such as 
packet radio. 

The LRPC and the Commission 
then tried to tackle the need for 
vastly more hams. The only ham 




QSL OF THE MONTH 

To enter your QSL, mail it in an envelope to 73, WGE Center, Forest 
Road, Hancock, NH 03449 f Attn: QSL of the Month. Winners receive a 
one-year subscription (or extension) to 73. Entries not in envelopes 
cannot be accepted. 

8 73 Amateur Radio • October, 1989 



system in the world which seemed 
to be working these days was the 
one adopted by the Japanese — a 
no-code license. Efforts to imple- 
ment this here were completely 
stopped by the ARRL directors. In 
frustration the FCC disbanded the 
LRPC and its NIAC committees, 
giving up on the whole emergency 
communications situation. 

All this is the background and, 
my apologies since I've covered it 
all before, but I find many ham 
memories seem to be incredibly 
short when it comes to the no- 
code debacle. A couple of hams 
have been pushing the FCC to 
deal with the problem of electro- 
magnetic pulses (EMP), so the 
few amateurs we have left will be 
in a better position to provide 
emergency communications 
should atomic bombs be used. 

Little has been published on 
how we can cope with this prob- 
lem. Indeed, we have little infor- 
mation on how much of a problem 
this really is! Some reports indi- 
cate that a high attitude bomb 
might wipe out most solid state 
equipment for a thousand miles 
around. Pffft would go all our HTs 
and mobile VHF gear— plus our 
low-band rigs — leaving us nothing 
with which to communicate. The 
Department of Defense (DOD) 
has been fighting to keep the FCC 
out of the EMP arena, saying 
there's plenty of information avail- 
able on how to guard against 
EMP. The hams replied that the 
key information on this is classi- 
fied — or, at best, apparently only 
available to large corporations, 

Can ham gear be protected 
against EMP so we would have a 
chance to do our thing in case of 
an atomic bomb? Unless data is 
made available to help us shield 
and protect our ham stations, and 
to help manufacturers build in by- 
passing and shielding, the only 
backup communications our 
country has in case of such an 
emergency will be completely out 
of business. 

Well, you say, the likelihood of 
an atomic attack is remote 
enough so all that is just the usual 
gloom and doom baloney. That's 
nothing I have to worry about any 

Continued on page 74 




TAFF 



PUBLISHER/EDITOR 
Wayne Green W2NSD/1 



EDITOR IN CHIEF 
Bryan Hastings NS1B 

MANAGING EDITOR 
Hope Currier 

SENEOR EDITOR 
Linda Reneau 

INTERNATIONAL EDITOR 
Amie Johnson N1BAC 

EDlTOFHAL ASSISTANT 
Joyce Sawtelle 

ART DIRECTOR 
Alice Seofield 

JAPANESE TRANSLATOR 
David Cowhig WA1 LBP 

AssociATESrreCH advisory 

COMMITTEE 

MikeBryceWBBVGE 

Michael Geier KB 1 UM 

Jim Gray W1XU 

Chuck Houghton WB6IGP 

Dr. Marc Leavey WA3AJR 

Andy MacAllister WA5ZIB 

Joe MoeH K&OV 

Bill Pasternak WA6ITF 

Mike Stone WB&QCD 

Arffes Thompson W7XU 



ADVERTISING 
1-60^525-4201 
1^00-225-5083 

SALES MANAGER 
Ed Verbin 

ADVERTISING SALES 
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ADVERTISING SALES 

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Lisa Nierneta 

MARKETING ASSISTANT 
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WGE PUBLISHING, 
INC. 

CHIEF FINANCIAL OFFICER 
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CIRCULATION DIRECTOR 

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TYPESETTING/PAGINATION 

Susan Allen, Linda Drew, 

Ru I h Benedict 

GRAPHICS SERVICES 
Dale Williams, Peri Adams 

GRAPHICS PHOTOGRAPHER 
Dan Groteau 



Editorial Offices 

WGE Center 

Petef borough, NH 03458-1 194 

603-525-4201 

Subscription Customer Service 

1-800-525-0643 

Colorado/Foreign Subscribers 

calM -303-447-9330 



Wayne Green Enterprises is a division 
of International Data Group, 

Reprints: The first copy of an arti- 
cle— $3.00 {each additional copy— 
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Magazine, WGE Center, Forest Road, 
Hancock, NH 03449. 







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• Automatic lock tuning function 
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• IF-20 Interface unit handset • DRU-1 Digi- 
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- PG-4H Interface connecting cable • PG-4J 
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Specifications and prices subject to Change without notice or obligation. 

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memory channels (10 channels for sep- 
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• High stability VFCX The dual digital VFOs 
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• Multiple scanning functions. Memory 
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QRX 



Number 3 on your Feedback card 



EDITED 8Y BRYAN HASTINGS NS W 



Kudos 



. . .to Brian Lloyd WBGRQN, for coordi- 
nating this month's Special Packet Issue, 
and especially for his editorial contribu- 
tions. His efforts in gathering the editorial 
material were key to the formation of this 
issue. Thanks very much, Brian! 

Home-Brew IV 

Contest Results 

iviwaiBaHiaaaaaamiiaaiaBaai 

The verdict is In for the top three articles 
for the Home-Brew IV contest! The four- 
member evaluation panel, consisting of Jeff 
DeTray NKlF t Perry Donham KW10, Bryan 
Hastings NS1B, and Walter Lewandowski 
WA2VSN. spent many hours in late July care- 
fully reviewing each candidate. The decisions 
were tough, as there were many fine entries 
from which to choose. 

First prize went to Michael Geier KB1UM, 
for "Ravorig!*\ his inexpensive and simple 
conversion of a Radio Shack Fiavoradio™ tran* 
sistor AM radio to a 5 watt 30m C W transceiv- 
er The second prize went to Ron Cole K40ND 
for the "Bitchaser," a totally home-brew com- 
prehensive piece of test gear designed espe- 
cially for digital circuitry. Third prize went to 
William Lazure KB5CTH for his elegant ver- 
sion of a stable sensitive 60 Hz-1G0 kHz fre- 
quency meter. 

These top three articles will appear in the 
November 1989 issue. Thanks to all who par- 
ticipated! For those of you who didn't make it, 
be sure to look out for the announcement for 
the Home-Brew V contest in 1990. 

Shockley SK 

William Shockley, co-inventor of the 
transistor and Nobel Prize winner whose 
later life became embroiled in controversy 
over his racial theories, died of cancer at 
his home in Stanford. California- He was 79 
years oW. 

Shockiey shared the Nobel Prize for 
physics in 1956 with his colleagues from Bell 
Laboratories, John Bardeen and the late Wal- 
ter RBrattam. The team's first semiconductor 
device, developed in 1947, was an innovation 
that made the electronic age possible. Shock- 
ley Semiconductor Co,, the company he 
founded after leaving Bell labs in 1954, was 
instrumental in the birth of the Silicon Valley 
electronics industry. His former employees 
later invented the integrated circuit and the 
microprocessor. 

Shockley's later life was marked by bitter 
controversy over his claims that intelligence 
was genetically determined, and that blacks 
were genetically inferior and as a group could 
not be as bright as whites. His claims con- 




Guess who's a 50-year member of the 
League? Wayne W2NSD/1, "shows off" his 
plaque from theARRL. . , 

tributed to debate over the use of IG tests in 
schools and over why black Americans failed 
to score as well as whites, an outcome most 
experts blamed on biased tests and other fac- 
tors not related to genetics. 

ARRL Pro No-Code 



The ARRL is getting with the program at 

long last! Tfteir Board of Directors ruled in 
favor of adopting a no-code license class. On 
21-22 July, after an extensive and sometimes 
heated discussion, and by a vote of nine Direc- 
tors in favor to six opposed, they agreed that 
the ARRL will present a proposal recommend- 
ing a codeless class of amateur license to the 
FCC, This proposal for the new class of li- 
cense—to be called "Communicator"— wilt 
be in the form of a petition for rulemaking. 

The examination will consist of Novice-writ- 
ten Element 2 and an expanded Technician- 
written Element 3A having additional Ques- 
tions. These will include questions related to 
Morse Code, 

All license examinations will be given 
through the VEC examination system. To up- 
grade to Technician, the new licensee must 
pass a five-word-per-minute Morse code test 
also administered through the VEC system. 

Callsigns will be assigned from the Group D 
callsign block. Frequency privileges will be 
220 MHz and above, with output power limited 
to 250 watts. The no-code licensee will not be 
allowed to be the control operator of a re- 
peater or auxiliary station. 

J A WARC Bands 

Japans amateurs now have full access 
to the 1 8 and 24 MHz WARC bands. In 1979, 
the ITU created three new ham bands at 10, 
18 T and 24 MHz. In 1982, Japanese amateurs 



were granted privileges on 10 MHz t but it was 
not until 1 July that the other two bands were 
opened to them. The 18 MHz band is restrict- 
ed to Japanese First and Second Class li- 
cense holders, but 24 MHz is open to all oper- 
ators. 

Put This 
In Your Pipe 

A California ham Is suing Genera! Tele- 
phone due to their alleged discrimination 
against non-smokers* Craig Chambers 
WB6HTS of Los Angeles is making national 
headlines after filing suit against the giant 

telecommunications conglomerate. Accord- 
ing to Chambers, not only was his request to 
be placed in a non-smoking environment de- 
nied, but he soon found himseff called on the 
carpet by his superiors. He claims he was fired 
from his job after requesting a medical trans- 
fer to keep him away from tobacco smoke. 

Let's hope hams and non-hams alike appre- 
ciate Craig's fight for the right to work in an 
environment that is free of tobacco smoke. 
Send letters of support to Craig Chambers, 
2829 Warwood Rd., Lakewood CA 90712. 



UK Murder 



A ham and his wife have been murdered 
in Englandp and the police are asking hams 
to aid them In finding the killer, Peter Dixon 
G0HFQ and his wife Gwenda were last seen 
on Thursday, 29 June when they left on a 
camping trip to Howstone Farm near Little 
Haven in Pembrokeshire. Their bodies were 
discovered on S July. Both died of gunshot 
wounds and investigators say that they were 
killed within a half mile of their campsight 
Dixon's car was equipped with both HF and 
VHF amateur gear, Police are asking any 
ham. anywhere in the world, that may have 
contacted G0HFQ between 29 June and 5 
July to get in touch with them. Contact the 
Murder Incident Room of the Pembrokeshire 
Police at Haverfordwest 3721 . The STD code 
is 0437. If you are calling from outside the 
United Kingdom, request operator assis- 
tance. 

Merci Beaucoup 

Thanks to Westlink Report, RF Carrier, 
and Associated Press for providing items for 
this month's ORX. Keep your ham radio-relat- 
ed news items and photos rolling in to 73 
Magazine, WGE Center, Forest Rd- f Hancock 
NH 03449 t Atln: ORX, You may also submit 
text as E-Mail to the Sysop on the the 73 BBS. 
(603) 525-4438, 300/1200 baud. 8 data bits, no 
parity, and one stop bit. 

73 Amateur Radio * October, 1989 11 







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Number 4 on your Feedback card 



Packet Racket Lip Zipper 

Automatically turns off your rig's speaker during packet operation. 



by Michaef J, Geier KB1UM 



If you're like most of us frugal hams, 
you're using your 2 meter base rig for 
both voice and packet— and you're sick and 
tired of the awful packet screech and having 
to connect and disconnect cables every time 
you switch modes! Of course, you can solve 
these problems by buying another rig for 
packet, but why spend $500 when you can 
build the Packet Racket Lip Zipper for next to 
nothing? 

The Lip Zipper switches the audio output 
of your rig from an external speaker (or even 
the internal one, if an interrupting connector 
is provided on the radio) to the audio input 
of your TNC, In addition, you can use it to 
switch the rig's mike input between the mike 
andiheTNC. 

A glance at Figure I reveals how simple the 
Lip Zipper is. It takes its power from the I2V 
supply powering the rig and/or TNC, draw- 
ing minimal current. It senses activation of 
the TNC from pin 9 of the DB-25 serial 
connector, then energizes the relay. (Pin 9 on 
my MFJ 1270 TNC is connected to +12 
volts. If yours isn't, try using pin 6, the Data 
Set Ready connection. Anything that switch- 
es on and off with the TNC will do,) You can 
make the whole circuit from Radio Shack 
parts, and it will fit into a plastic 35mm film 
can or other handy container (see photo). 

Construction 

Use any construction technique you like. 
Nothing is critical here, although I do recom- 
mend shielded cable for all audio leads, in- 
cluding the speaker connections. Otherwise, 
RF hash from your computer can get into the 
TNC and cause problems. Of course, that can 
happen even without the Lip Zipper. 

First, connect the .sense wire to pin 9 (or 6) 
of the DB-25 on the back of your TNC. If you 
have a sealed, factory-made cable, you'll 
have to open its connector far enough to 
connect the wire. If that seems too difficult. 
you can open the TNC and connect to the 
PC board, running the wire out the back. 
But you'll void your warranty if you do it 
that way. 

Connections to your radio will depend on 
its make and model. Some rigs, like my trusty 
old KDK FM-2016A, have an accessory plug 
on the back that lets you interrupt the audio 
going to the internal speaker. If yours 
doesn't, you'll have m use an external 
speaker. Many base station ops do thai 
anyway* for the better sound. 





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C- TO AUOKJ INPUT OF TNC 

CORRECT GflOURO TO POWER SUPPLY NOT SERIAL 
CONNECTOR 



Figure I. Schematic for the Packet Racket Lip 
Zipper, 

When you're done, stuff the board into the 
container and put it out of sight. Since it has 
no user controls, you 
don't need it cluttering 
up the shack! 



Figure 2. Optional circuit for switching 
between mike and TNC 

erate normally. Now fire up the TNC The 
speaker should quiet immediately, and if 
you're using the optional circuitry* the mike 
should no longer work {although the PTT will 
still key the rig). 

Sit back and enjoy the quiet and conveni- 
ence of a dedicated packet station, When 
you # re ready to return to voice operation, just 
switch the TNC off and you're back on the 
air! 

Michael J. Geier KB I UM appears monthly as 
73*s Tech Answer Man in 4t Ask Kahoom. " 
You can contact him at 7 Simpson Court, S. 
Burlington VT 05403. 



An Option 

My accessory plug 
also has an audio input 
pin, originally intended 
for a DTMF pad. I con- 
nected it to the audio 
output of my TNC and 
it worked line, It 
doesn't seem to mind 
that the mike is still 
connected, but if yours 
does, just use the op- 
tional circuit shown in 
Figure 2* 

These extra connec- 
tions let you switch the 
rig's mike input be- 
tween the mike and the 
TNC T and they require 
you to get into your 
mike plug and add 
some wiring. Be sure to 
use shielded cable: the 
old "twisted pair" just 
won't do. 

Powering Up 

With the Lip Zipper 
installed, turn on your 
2 meter rig. Leaving the 
TNC off. Your mike 
and speaker should op- 



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73 Amateur Radio • October, 1989 13 



Number 5 on your Feedback card 



Setting Up a 
Packet Radio Station 

An excellent guide for beginners and veterans alike. 



by Brian Lloyd WB6RQN 



You may be just joining the packet radio 
revolution or you may have been using 
packet for a while. Either way, this step-by- 
step guide to setting up a working, reliable 
packet station is here to help you. You begin- 
ners, and those of you just getting interested, 
will find simple advice that's unavailable in 
any book. Those of you who are experienced 
packeteers will learn how to gauge the perfor- 
mance of your radio when you use it as part of 
your packet station. 



What System to Put Together? 

There are just a few components to the 
basic system— the transceiver, the terminal 
(or personal computer), and the Terminal 
Node Controller (TNC) or data controller. 
The TNC "interfaces" the rig and the PC— 
that is , it goes in-line between the two- The 
following few sections discusses these three 
components. 

#1 - The TNC/Data Controller 

Until a few years ago, the only interface 
was the TNC. Most TNCs contain two 
devices, a modem (MOdulator/DEModula- 
tor) and a packet assembler/disassembler 
(PAD) . A modem is a device that converts the 
digital pulses from the computer to a form the 
radio can use to modulate a carrier wave, and 
vice versa. The PAD converts the data stream 
coming from the computer into discrete 
groups— called "packets**— which go on to 
the transmitter. It also converts the packets 
arriving from the receiver into a continuous 
data stream that goes on to the PC, which 
interprets the data as text and prints it onto the 
monitor. 

Nowadays there's a little more selection. In 
the last few years, data controllers — devices 
that can encode/decode other digital modes 
such as RTTY , AMTOR, and CW in addition 
to packet, appeared on the market. These are 
also called multimode or all-mode con- 
trollers. Examples of these are the AEA PK- 
232, the MFJ 1278, and the Kantronics 
KAM. You just put them in in place of the 
TNC. 

Even newer to the market are boards that 
plug into your computer to make it a complete 
packet radio system, except the transceiver. 
(See the review of the DRSI Packet Adapter 
in this issue.) The plug-in board approach is 
pretty much limited to the IBM-PC and com- 
patible computer systems. Most of the plug- 
in boards offer an on-board modem so that the 

14 73 Amateur Radio • October, 1989 



computer may be plugged directly into the 
radio, You won't need a cable or another 
piece of hardware* 

If you plan to get into packet very seriously 
and/or are an avid experimenter, the plug-in 
board is probably the best way to go. It can 
also be the least expensive since many of 
these boards give you connections for two 
radios (it's like having two TNCs). The soft- 
ware available for the plug-in boards tends to 
be more powerful because it can take advan- 
tage of the computing power of the PC — a 
much more powerful computer than the TNC 
or data controller. If you want to operate on 
HF and you have chosen the plug -in board 
approach, don't worry; many vendors offer 
external modems optimized for HF opera- 
tion, which you can attach to one of the serial 
ports on the plug-in card. 

If you are interested in operating packet 
and you want to operate RTTY, CW, and/or 
AMTOR, choose a multimode device. They 
provide all the modes of operation and usual- 
ly include a special modem and tuning indica- 
tor that is optimized for HF operation, When 
you select packet operation in any of the mul- 
timode devices they perform as ordinary 
TNCs. 

If, like most packeteers, you plan to use 
packet on VHF for local communications, the 
TNC is your best bet. This is the traditional 
way to construct a station and, in many cases, 
is also the least expensive way to go* 

#2 - The Transceiver 

For VHF operation most packeteers use a 
standard VHF NBFM radio. Since most 
packet operation takes place on only a few 



COMPUTER 



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B 



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20 



L 



Figure L RS-232 cable pin connection be- 
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frequencies, an old crystal -controlled rig is a 
good choice. On 2 meters, much of the packet 
activity goes on between 145.01 and 145.11 
MHz. 

Consider also transmitter power. Packets 
need a good signal-to-noise ratio to get 
through reliably* It really doesn't hurt to have 
a 25W transmitter. A handy-talkie may be 
convenient but its 2W output can make a link 
marginal* 

On the same token, it's especially impor- 
tant in packet radio to have a good receiver 
and antenna* You should be able to hear those 
stations that hear you. This is because packet 
is a simplex mode— it operates on only one 
channel. Thus, a packet station listens on the 
channel and does not transmit until it senses 
that the channel is clear, If two or more pack- 
et stations transmitted on the same channel 
simultaneously, then those packets would 
'collide,** causing their corruption. For 
packet to work well it is important to hear all 
the other packet stations in your area. If your 
system can't hear another station, it may 
think the channel's clear when it may actually 
be busy, and so transmit, causing a collision. 

Effective HF packet operation requires a 
very stable rig that can be tuned within 20 Hz 
of the desired operating frequency. If you 
have an analog rig* consider crystal control 
for the frequencies you plan to use. (HF pack- 
et tends to operate on just a few frequencies). 
If you have one of the newer digital rigs that 
use a PLL for frequency control, consider 
getting the high accuracy option (usually a 
temperature-compensated crystal oscillator 
or a crystal oven). 

You want also to have a good 500 Hz band- 
width receiving filter. Filters in the modem 
are no substitute for a good crystal or me- 
chanical filter in the receiver's IF, For best 
performance, AGC sampling must take place 
AFTER the selectivity, not before. If you use 
a wide filter, an unwanted signal in the re- 
ceiver's passband can cause a change in the 
receiver's AGC even though the signal 
doesn't otherwise interfere with the packet 
signal you are trying to receive. The gain 
change can conftise the modem and make the 
packets unreadable* 

Packet, like AMTOR, likes a fast transmit/ 
receive switching time on the radio* The re- 
ceiver must recover very quickly after trans- 
mitting so you can reliably receive the 
acknowledgments from the other station. Al- 
though a slow transceiver can be made to 




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73 Amateur Radio • October. 1989 15 



work, it requires both stations to make adjust- 
ments in the transmitter keyup delay value 
(TXDELAY) in the TNC. (See the discussion 
on setting TXDELAY later in this article). 

#3 - The Computer or Terminal 

If you acquire a TNC you need a computer 
or a computer terminal to display the data, if 
you choose to use a computer terminal it 
should be capable of asynchronous ASCII 
operation, A terminal usually has everything 
you need to communicate with the TNC built- 
in, so all you need to connect the terminal to 
the TNC is a cable (see below}. 

Computers are inherently dumb and must 
be told what to do by software programs . If 
you are operating with a multimode device or 
a TNC you need a program for the computer 
that allows it to operate as a terminal. Most 
vendors of TNCs and multimode devices of- 
fer programs for the more popular comput- 
ers, These programs are tailored to packet 
operation and include features that make op- 
erating packet radio more efficient, simple, 
and enjoyable. On the other hand, almost any 
program designed to allow the computer to 
operate with a modem— such as Crosstalk or 
Procomm— works fine. 

If yon get the add-in board you'll need 
some special software. This software should 
come with the board, usually in the form of 
one or more computer diskettes. Some 
boards have publicly-available software, 

Connecting the TNC to the Computer 

If you choose the add-in board approach, 
the connection is handled internally in the 
computer. The manufacturer's instructions 
tell you how to properly configure the 
jumpers or switches on the board. 

If, however, you have a TNC or multimode 
controller, obtain a cable to connect the 
device to your computer or terminal. In order 
for your personal computer to "talk" to a 
TNC, make sure that it has true asynchronous 
RS-232 serial port. (Some less expensive 
computers do not adhere to RS-232 signal 
level specs* These computers may not work 
well with some types of TNC) A serial 
port is one that accepts digital data serially— 
that is, one bit at a time. Most serial port 
connectors on computers are either DB-25 
males or DB-9 females. Then buy or config- 
ure an RS-232 cable with the appropriate 
connectors. 

Some computers, such as the ever-popular 
Commodore-64 and the VIC* 20, have TTL 
signal levels at their serial ports. You have 
several options here: find a TTL/RS-232 lev- 
el converter interface, or get a TNC/data 
controller that uses TTL signal levels rather 
than RS-232, 

The simplest cable for connecting the TNC 
to the terminal requires only three signals: 
transmit data, receive data, and ground. On a 
standard DB-25 RS-232 connector these are 
pins 2, 3, and 7, respectively. Try the * 'three 
wire" connection first to see if it works. 
Connect the TNC to the terminal, turn on the 
terminal, then turn on the TNC. Something 
should appear on the screen (although it may 
be random "garbage" characters). If you get 

16 73 Amateur Radio * October, 1989 



absolutely nothing on the screen, your termi- 
nal or computer probably requires some of 
the RS-232 control signals in addition to the 
transmit and receive data signals. Try con- 
necting the signals * 'Data Set Ready" (pin 6). 
"Data Carrier Delect" (pin 8), and "Data 
Terminal Ready" (pin 20) together at the 
terminal/ computer end of the cable. You 
should now get something on the screen when 
you turn on the TNC. 

The next step is to ensure that the comput* 
er/termiiial and the TNC are sending data to 
each other at the same speed (baud rate) and 
format. Most packeteers use 4800 or 9600 
bauds between the TNC and the terminal with 
8 data bits, no parity, and one stop bit. Set the 
terminal or your terminal program to the de- 
sired baud rate and these parameters. Some 
TNCs have a switch on the back that lets you 
set the data rate. In that case, set the baud rate 
on the TNC to the desired value. 

Some TNCs have no external switch for 
baud rate. These TNCs have an autobaud 
routine that automatically determines the 
baud rate used by the terminal. Usually you 
wait until a legible message from the TNC 
appears on the screen of your terminal, then 
you press a specific key on the keyboard. At 
this point there should be communications 
between the TNC and the terminal in both 
directions. 

Sometimes your terminal can see what the 
TNC is sending bm the TNC appears to ig- 
nore everything you type. This is usually a 
problem with the RS-232 connection. If this 
occurs, try connecting the 'Request To 
Send" signal (pin 4} to the ** Clear To Send" 
signal (pin 5) at the terminal or computer 
RS-232 connection. 

At this point the terminal and TNC should 
be communicating. If every character you 
type appears twice on the screen, set your 
terminal or computer for full-duplex oper- 
ation. 

This is a good time to set the terminal 
control parameters of the TNC. Every TNC 
or multimode controller has some preset or 
default values for its control characteristics. 
You can change these parameters to make the 
TNC more compatible with your terminal. If 
you are using a CRT terminal or <* computer, 
enter the command BKONDELGN* After this 
command the TNC erases characters on the 
screen when you press the backspace key on 
the keyboard, Some terminals generate the 
ASCII rubout (delete) code instead of the 
ASCII backspace code when the backspace 
key is pressed (DEC VT-100 and compatible 
terminals). You can tell that this is happening 
if you make a mistake then correct it with the 
backspace key, and the TNC docs not recog- 
nise what appears to be a perfectly valid com- 
mand. You can tell your TNC to recognize 
your backspace key with the commands 
delete S7F or DELFTEON. Read the manual 
that comes with your TNC to find the appro- 
priate command. 

Many terminals and terminal programs 
provide some son of line wrapping function. 
This means that if you type beyond the end 
of a line your typing continues on the next 
line. The TNC also provides this feature. 



If both are turned on, you see text on every 
other line whenever the text extends beyond 
the end of the line. To prevent this, either 
turn off the line wrapping at the terminal or 
send the following command to the TNC: 

SCREENL0. 

This is the time to experiment with sending 
commands to your TNC. You can get a feel- 
ing for how it works before you hook it up to 
the radio. 

Connecting the TNC to the Radio 

Perhaps the single most important thing 
you can do to ensure reliable packet operation 
is to properly connect and adjust the TNC to 
the radio. First, decide where to connect the 
two. Many transmitters offer a high-level 
auxiliary input. Use this input instead of the 
microphone input if possible. Many micro- 
phone inputs do some equalization or signal 
processing that can distort the signal generat- 
ed by the TNC thereby making it difficult for 
other stations to decode your packets- The 
signal at the aux input often bypasses these 
stages and provides better performance. 

The audio from the receiver needs to get to 
the TNC. Although the signal from the speak- 
er may work, it is almost always distorted by 
the audio amplifier. The result is that the 
TNC fails to decode otherwise good packets, 
Many radios offer a low-level audio output 
for a phone patch or selective calling unit. 
This low-level output is a much better choice 
than the speaker jack. If your radio docs not 
offer a low-level output, try taking the signal 
from the **hoE T ' side of the volume control. 

Once you have the TNC connected to the 
radio, adjust the transmit signal level so that 
the signal from the TNC properly modulates 
the transmitter, Proper adjustment here is 
critical for good results. There are two tech- 
niques for setting the transmit level of an 
NBFM transmitter. 

The first technique requires a deviation 
meter. Set up the deviation meter to read the 
deviation of the transmitted signal. Turn on 
the transmitter and the TNC and enter the 
calibration command. If your TNC offers the 
option of selecting either the high or low 
tone, select the high tone and adjust the signal 
level at the TNC for 2.5 to 3 kHz of deviation. 
If your calibration command alternates be- 
tween the mark and space tones at a rapid rate 
(Kantronics' calibration command does this) 
set the level at the TNC for 2.0 to 2,5 kHz of 
deviation. 

The second technique does not require a 
deviation meter but it does require a receiver 
and an AC voltmeter. Connect the voltmeter 
to the output of the second receiver so that 
you can get a relative indication of audio 
output. Set the frequency of the receiver to 
the output frequency of your TNC/radio pair* 
Tum on the transmitter and the TNC and 
enter calibration mode. Select the high tone 
and increase the TNCs transmit signal level 
until further increase of the level at the TNC 
no longer results in an increase in the level 
indicated by the AC voltmeter connected to 
the second receiver, Note the reading on the 
voltmeter. Now decrease the signal level at 
the TNC until the voltmeter connected to the 

Continued on page tS 



Number 6 on your Feedback card 



Ha m profiles 

There are no "average " hams! 



Career Aims Shaped 
by Radio Theory 

Elan Grossman KA2RMW, age 
20. got his ham ticket at age 14, 
after enrolling in Carole Perry 
WB2MGP's course at Intermedi- 
ate School 72 in Staten Island. 
New York. He is presently an un- 
dergraduate at Westeyan Univer- 




Elan Grossman KA2RMW^a 
young ham active in astrophysics. 



sity, majoring in both physics and 
astronomy. He just finished a 
research apprenticeship at Wes- 
leyarTs Van Vleck Observatory 
(which houses the largest tele- 
scope in Connecticut) working on 
a project to study physical proper* 
ties of stars under formation and 
to search for possible planets 
around them, Elan also works with 
a 20-mch Alvan Clark refractor 
that records the apparent parallax 
shift in nearby stars, a way of de- 
termining their distances. 

Elan is also part of a project un- 
der grant to conduct research on a 
new form of radiation detector that 
would be able to measure the 
quantity of radiation to which a 
person has been exposed. He a^ 
so taught gifted high school youth 
during the summer 

Elan's future plans include a 
Ph.D. in either astrophysics or 
planetary science. He says the 
knowledge he gained in radio the- 
ory played a significant role in 
shaping his interests in electrody- 
namics and radio astronomy. 



Young Ham of the Year 

Erin McGinnis KA0WTE, age 
18, of Topeka, Kansas is this 
year's Westlink Report "Young 
Ham of the Year/' This Tech li- 
censee was chosen for this high 
honor because of her ongoing 
dedication to amateur radio public 
service activities, disaster pre- 
paredness work, and publiciza- 
tion of amateur radio. She regular- 
ly participates in civic events such 
as net control for the Washburn 
University President's Rowing 
Regatta, the Annual Railroad 
Days Commemorative, and the 
Exxodusters Parade. Erin also 
displays amateur radio at emer- 
gency preparedness exhibits, is a 
regular member of the local ARES 
operation, and participates in 
each Reld Day. 

Erin organized press releases 
and interviews for the local and 
the national electronic press, and 
assisted in the preparation of a 
city resolution declaring Field Day 
to be "Kaw Valley Amateur Radio 
Club Week" in Topeka. She also 
organizes and teaches the club's 
fall Novice training class. 

Erin is a recent Honor Roll grad- 
uate of Topeka High School 
where she maintained a straight 




Erin Mc Ginnts— Young Ham of 
the Year. 



"A" average during her Senior 
year. High school activities includ- 
ed dramatics, drill team, debate 
squad, various social functions 
and. of course, amateur radio. 
She also held a part-time job. 

Erin comes from an a II- 
ham family; Her father is Steve 
N0HGX, her mother is Linda 
N0HGY, and brother Matt is 
KAGWTF. Her primary ham inter- 
est is chatting with the British 
Isles. She intends to use amateur 
radio to keep in contact with 
her family from Emporia State 
College. 



Feed b a ck 



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Feedback^ Title 

1 Welcome Newcomers 

2 Never Say Die 
3QRX 

4 Home-Brew; Packet Racket 
Lip Zipper 

5 Setting Up a Packet Radio Station 

6 Ham Profiles 

7 Review: DRS1 PC*Packet Adaptor 

8 Home-Brew; SX-64 Runs Digicom! 

9 Digital Dreams 

10 Home-Brew: lC-22Son Packet 

11 Home-Brew: One-Chip RS-232 
for the C-64 

12 Let the TNC Work 
While Your PC Sleeps 

13 Packet Radio in Japan 

14 Home-Brew: Standardizing the 
Radio/TNC Interface 

J 5 Review: GRAPES 56 Kb Modem 

16 Packet Radio and 
High-Tech Nomadics 

17 Home- Brew: Improve Your 
TNC's DCD Circuit 



Feedback* Title 

18 TexNet Packet Switching Network 

19 Home-Brew: KAM Bo* 

20 Amateur Packet Networking 

21 DXDA Awards 

22 TCP/IP for the Macintosh 

23 Vertical Antennae :it HP 

24 Home- Brew: HF Packet 
Tuning Aid 

25 New Products 

26 Home-Brew: The Quickchanger 

27 Index: 10^89 

28 Ad Index 

29 Special Events 

30 Letters 

31 Updates 

32 73 International 

33 Dealer Directory 

34 Barter V Buy 

35 Propagation 

36 Review; DX Helper 

37 Ham Help 

38 Tech Tips 

39 Review: Flodraw 



7$ Amateur Radio • October, 1989 17 



Continued from page 16 

receiver reads about six to seven tenths of the 
maximum reading previously noted. Your 
deviation is now set. 

Kantronics seems to be a special case when 
it comes to setting the signal level coming 
from the TNC. The Kantronics unit uses a 
jumper rather than a trimpoi for setting the 
signal level. The result is that you have only 
three choices for signal level. You may well 
need to change one of the resistors that deter- 
mines the transmit signal level. In my KPC-2 
I replaced the resistor with a trimpot so that I 
could vary the level according to need. 

Getting On The Air! 

If you have performed all the steps up to 
this point your station is ready to put on the 
air. Now it is time to enter the control com- 
mands for the TNC (the add-in boards have 
their own unique command set so you need 
to determine on your own which paramet- 
ers you need to change). Here is a verbatim 
list of commands to enter: AX25L2V2 on, 

MAXFRAME t, MYCALL WB6RQN (put your 
own call in on the last command), 

The First command enables the later ver- 
sion of AX, 25. (AX, 25 is a "protocol" 
agreed on by many packet stations.) The sec- 
ond command allows the TNC to send only 
one packet before waiting for an acknowledg- 
ment. The last command sets your callsign in 
the TNC (some TNCs will not operate until 
you enter your callsign). 

The next step is to determine the proper 
setting for the TXDELAY command. 
TX DELAY determines how long the TNC 
waits after keying the transmitter before it 
actually begins sending data. This value is 
different for every radio and you must take 
into account the amount of time that it takes 
for the transmitter to turn on and for the 
remote receiver to begin decoding your pack- 
ets. The default value for TXDELAY is usu- 
ally 300 ms. This means that the TNC begins 
sending data 300 ms after the TNC keys the 
transmitter. For voice this is a pretty short 
time but for packet it is quite long. It is a good 
idea to try to shorten this time if possible, 

Determining the proper value for TXDE- 
LAY is not difficult and takes only a few 
minutes. It requires two stations so it is prob- 
ably a good idea to get together with other 
paeketeers to perform this operation. Desig- 
nate one station as the receiver and have its 
operator turn on monitoring (MONITOR 
ON). Perform this sequence of tests off the 
air (use a dummy load) or on an unused fre- 
quency since no one else can use the frequen- 
cy while you are testing, The process: 

1 . Open the squelch on the receiver so that 
the TNC is receiving unsquelched noise. 

2. At the transmitter set TXDELAY to 
some low value, say 10 ms (for most TNCs 
the value for this is 1). 

3. Enter a beacon text and enable beacon 
every three seconds with the following com- 
mands: BTEXT TESTING BEACON BVtfKY 3, At 

this point the transmitter should key every 
three seconds and you should hear "packet 
racket*' at the receiver. You may or may not 
see packets displayed on the screen at the 
receiver. 



4, Enter higher and higher numbers for 
TXDELAY until the receiver begins display- 
ing the beacon packets, The value of TXDE- 
LAY is the amount of time it takes the trans- 
mitter to switch from receive to transmit and 
begin sending valid data. Remember this val- 
ue as the transmitter switching time, 

5. Now close the squelch on the receiver 
(no noise between packets). The receiver 
should stop displaying the beacon packets. 

6, Continue to increase the value of TXDE- 
LAY at the transmitter until the receiver 
again begins displaying the beacon packets. 
The difference between the previously deter- 
mined transmitter switching time and the cur- 
rent TXDELAY is the receiver's squelch 
opening time. Tf this turns out to be a very 
long time, i.e. longer than about 100 ms, I 
suggest you get a different receiver. For ex- 
ample, my ICOM IC-245 has a squelch open- 
ing time of 50 ms. 

7. Perform the above sequence of tests for 
every receiver and transmitter. 

8, Set TXDELAY for each transmitter by 
taking the transmitter keyup delay (calculated 
in step 4) and adding it to the longest squelch 
opening time of all the receivers tested. 

9. Turn off beaconing at the transmitters 

(BEACON EVERY 0). 

Some recciver/TNC combinations work 
properly with the squelch left open on the 
receiver. If the carrier detect light on the front 
of the TNC does NOT come on with receiver 
noise (squelch open) but does come on when 
receiving packets, leave the squelch open at 
all times. If the carrier detect light is on with 
noise you have no choice but to close the 
squelch. 

Cutting Down on Collisions 

Now is the time to set the parameters that 
control channel sharing. Check the manual 
and determine whether or not your TNC has 
the commands persist and slottime. The 
presence of these commands indicates that 
your TNC supports the more advanced chan- 
nel sharing technique called P-persistent 
CSMA (Carrier-Sensed Multiple Access). 
P-persistent CSMA helps to prevent several 
stations from trying to transmit at the same 
time if they all have data to send at the same 
time. 

You may have an older TNC that doesn't 
support the slottime and persist com- 
mands. In that case you need to use the 
DWAIT parameter. The original purpose of 
the DWAIT parameter was to prevent a sta- 
tion from colliding with or * 'stepping on" a 
digipeateras it retransmits packets. When the 
channel is clear, i.e. when no one else is 
transmitting, and your TNC has data to trans- 
mit, your TNC waits for the length of time 
specified by DWAIT before keying the trans- 
mitter. This fixed waiting period is a draw- 
back because two or more stations that have 
data to send wait patiently for the period 
specified by DWAIT and then transmit at the 
same time, guaranteeing a collision. The 
TNCs that support P-persistent CSMA vary 
this time based on the slottime and persist 
commands so that there is much less likeli- 
hood of a collision. 



If your TNC does not support P-persistent 
CSMA, then set the value of DWAIT to be 
about twice the largest TXDELAY value for 
all the stations in your local area. This gives 
those stations with P-persistent CSMA a rea- 
sonable chance to get a transmission in ahead 
of a station that does not have P-persistent 
CSMA. Don't worry: The P-persistent CS- 
MA stations sometimes wait longer periods 
so they will often let the other stations trans- 
mit first. 

If your TNC supports P-persistent CSMA 
{which it does if it has the persist and slot 
time commands) then first enter the follow- 
ing command: dwait o. This disables 
DWAIT and allows the persistence feature of 
the TNC to control channel access. 

Next, set the value for slottime equal to 
the largest TXDELAY value for all of the 
packet stations in your area (all stations in a 
given local area should have the same value 
for SLOTTIME). For instance, if the largest 
TXDELAY is 26 (260 ms) set slotttme also 
to 26, 

The value of PERSIST is a function of the 
number of other stations also using the fre- 
quency. The formula is: P = 255 x (1/n), 
where *'*P** is the value to be entered to the 
PERSIST command and 4i n" is the number of 
other stations (beside yourself) using the 
channel. For example, if you are having a 
QSO and there are four other stations that 
have QSOs of their own, then there are a total 
of five stations besides yourself on the fre- 
quency. Using the formula above you calcu- 
late P to be: 255 x (1/5), or 51. In this case 
you enter the command: PERSISTSL If you do 
not want to spend time calculating the best 
value for persist a good guess is to set it to 
64. This keeps your station from being a bad 
neighbor most of the time, although it slows 
things down somewhat when your QSO is the 
only one on the channel. 

Frame Acknowledgment (fraCK) 

The last parameter to set is the frame ac- 
knowledgment timer (frack). This is the 
amount of time the TNC waits for an ac- 
knowledgment after transmitting a packet be- 
fore it assumes that the packet was lost. Most 
TNCs set the frack value too low and a 
problem occurs when the channel is busy, 
The receiver may receive the packet without 
any problem buL due to channel activity, may 
not be able to send an acknowledgment within 
the time allotted by the sender. In these cases 
the sender must resend the packet, 

The solution to this problem is to increase 
the value of frack , Start out with 1 seconds, 
set with the command: frack jo. With a lot of 
channel activity, set frack to 15 or even 20 
seconds* (Some TNCs won't accept a value 
higher than 15 seconds.) 

Operating 

At this point your station is set up and ready 
for operation. To connect to another station, 
for instance WB6RQN, type and enter the 
command: connect WB6RQN and wait for the 
"CONNECTED" message. Tf the other sta- 
tion is too far away to reach directly you may 
need to use an intermediate digipeatcr. To 



18 73 Amateur Radio * October, 1989 



connect to WB6RQN via the W3ABC 
digipeater the command is: connect 
WB6RQN via W3ABC, To add a second 
digipeater, e.g. W4XYZ, to the string the 
command is: connect WB6RQN via W3ABC, 
W4XYZ, You are allowed up Eo eight 
digipeaters between you and the destination. 
It's unlikely, though, that you could maintain 
reliable communication with more than two 
digipeaters between you and the destination, 
unless the links are unusually strong and 
channel activity very light 

Many people discover that their TNC of- 
fers a mode that automatically transmits a 
boacon packet (remember we used that fea- 
ture to calculate the TXDELAY value). At 
first thought, this appears to be a good way lo 
tell others that you are on the air and looking 
for a QSO. On the other hand, imagine what 
things would be like if everybody transmitted 
a beacon. So much channel capacity would be 
used to send beacons that precious little 
would be left to send data. This is, in fact, 
what happens, to the ire of everyone. No r 
beaconing is a bad idea. Avoid it like the 
plague! 

To make a QSO it's much better technique 
to listen first and then pick a station to try to 
contact. To ease this process most TNCs of- 
fer the mhearo command. When you enter 
the mheard command, the TNC displays the 
callsjgns of the most recently heard stations. 
Use this as a guide to the other stations cur- 
rently on the air- 

There is much more to learn about Bulletin 
Boards and Network Nodes but that is beyond 
the scope of this article, and is amply dis- 
cussed in other articles in this Special Packet 
issue. Following the procedures outlined 
here lets you extract the maximum perfor- 
mance from your station so that you can 
spend your time operating, learning about, 
and enjoying the fascinating hobby of packet 
radio, 73 and happy packeting! 



Brian Lloyd WB6RQN has pursued amateur 
radio enthusiastically since age eight. He re- 
cently co-founded Sinus Systems t a network- 
ing business in Petersburg. Virginia. You 
may reach Brian at: 5712 Still well Rd., 
RockvUte MD 2085 L 




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73 Amateuf Radio » October, 1989 19 



Number 7 on your Feedback card 



73 Review 



by Brian Lloyd WB6RQN 



DRSI PC* Packet Adaptor 



Revolutionizes the PC/transceiver interface. 



DRSI 

2065 Range Road 

Clearwater FL 34625 

Tel: (800) 999-0204. 

Price Class: S14CM 70. 

(three models) 



Do you have an IBM-PC/XT/ 
AT computer and operate 
packet radio? If so. you will want 
to take a serious look at the DRSI 
PC 'Packet Adaptor (PCPA). This 
board plugs into your IBM or com- 
patible and turns tt into a complete 
packet radio communications sys- 
tem. With the PCPA, you no 
longer need a TNC; the PC* 
Packet Adaptor has all the func- 
tions of a TNC t and then some. 
The software thai comes with the 
board lets you operate it as a TNC, 
a bulletin board, a Net/ROM node, 
and a TCP/IP network host. This 
product is one of the most significant to ap- 
pear on the packet scene. 

Product Description 

The PCPA arrived in the mail. Inside the 
surprisingly small box was a user's manual, a 
hardware manual, a get-started-right-now 
sheet, four 5V*" diskettes, and the PCPA ft* 
self. All the material appears to be of high 
quality, and the board has sockets for all chips 
so that repairs should be easy if a problem 
occurs. 

The PCPA board uses the standard half- 
card format tor the PC. You can plug it into any 
slot in any PC/XT/ AT compatible computer 

system. The board is available in three ver- 
sions, depending on the type of interface de- 
sired. The type one board supports one 1200 
bps Bell 202 modem {for VHF packet) on- 
board, and one RS-232 port for interfacing an 
external modem. The type two board (the ver- 
sion reviewed) has two built-in 1200 bps 
modems. The type three board has two 
RS-232 ports and no on-board modem. 

If you plan to experiment with modems or to 
operate on HF. you will probably want the type 
one or type three board. If, however, you want 
to operate on multiple VMF frequencies, the 
type two board is a better choice, if you are 
unsure, get the type one board. You can al- 
ways attach a Bell 202 modem to the RS-232 
port for dual VHF operation. 

The on-board modem I used, the TCM3105 
from Texas Instruments, isasingte 16-pin DIP 
occupying little space on the board. Along the 
top edge of the board are the modem's ptt 
and earner detect status LEDs. Each modem 

20 73 Amateur Radio • October, 1989 




The DRSt PC * Packet adaptor interface board. 

also has a watchdog timer to prevent a hard- 
ware or software error from keeping your rig 
key-down forever. Additionally, the modem's 
transmit and receive signal level controls 
provide compatibility with just about any radio 
configuration 

The PCPA has a feature that i have not seen 
in any other board for the PC; you can run up 
to four PCPA boards in the same PC f and all 
the boards can share the same IRQ line. Imag- 
ine having eight packet radio channels con- 
nected to your PC! 

Installing the Board 

Type two t the board I reviewed, has two 
radio ports. I constructed cables to attach it to 
my 2m and 70cm rigs, without any major prob- 
lems. Radio hookup was straightforward— as 
easy as hooking up any TNC. Since the board 
is inside the PC, there is no TNC-to-computer 
connecting cable or the hassle that goes 
along with it, 

Before installing the board, you must select 
the interrupt request line (IRQ) and the I/O 
address so no conflicts with other devices in 
the computer will arise. The boards come con- 
figured for IRO-7 and I/O address 300K Un- 
less you have many strange devices in your 
computer, the default values will probably 
work just fine. 

If you are using a local area network or have 
two printers connected to your computer, you 
may have conflicts between these and the 
PCPA. requiring you to change the IRQ line, 
the I/O address, or both. II you need to change 
the IRQ line, you can select IRO-2 through 
IRQ-7. If you need to change the I/O address. 



you can select 300H or 31 OH. The 
documentation is quite clear on 
how to detect and avoid these 
problems. 

After you have installed the 
board, do not replace the PC's 
cover at once. You will need to get 
at the board to calibrate and set 
the signal levels. 

Software 

One of the strengths of the PC- 
PA is that it comes with so much 
software— the basic PC/TNC 
package; the "BB" bulletin board 
package by AA4RE; PC/Node; 
NET/ROM; BBS package by G8BPQ T and the 
KA9Q TCP/IP "Net" package. You must de- 
cide what your objectives are so you can 
choose which software packages to install. 
Since I had enough room on the disk, I chose 
to install everything the four disks offered. 

The PC/TNC package is installed first, It 
contains the driver for the board, the TNC 
emulator, and the calibration software. The 
board and system are ready to use, unless you 
have a conflict with one of the other boards in 
your system and have changed the switch 
settings, Then you will need to run the Install 
command. This makes the necessary 
changes to the software packages so they will 
recognize your board when it has been recon- 
figured. 

After installing the basic software, you can 
run the calibration program. It is a good test to 
see if the board is working. If anything strange 
happens, you can bet that there is a conflict 
between the PCPA and one of the other 
boards in your PC. I did run into a conflict, and 
it showed up during calibration. I removed the 
conflicting board temporarily, and calibration 
proceeded without a hitch. Then I changed the 
switch settings on the PCPA to eliminate the 
conflict. 

Changing the switch settings required 
running the Install program provided with the 
PCPA, This process is clearly defined in the 
documentation so there was no problem. 

The next step was to run the background 
TNC program. This program is a terrninate- 
and-stay resident (TSR) program that runs on 
the PC in the background and provides all the 
features of a TNC. There are two flavors of this 



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program: TNCTSR-S and TNCTSR-L The lat- 
ter is larger, Although TNCTSR-L has more 
buffers so you can store more messages and 
data when operating unattended, I found that 
TNCTSR-S had more than enough buffer ca- 
pacity for my use. 

To interact with other users, DRSI provides 
two TNC communication programs: TNC- 
TERM and THS (The Hostmode Server). TNC- 
TERM looks and operates like a dumb termi- 
nal connected to a TNC running the WA8DED 
code. This is what I run in my old TNC-1 , so J 
was immediately at home with this software. 
The problem with TNCTERM is that it is not 
very "pretty;" it has no windows or special 
buffers for brag tapes, for example. It is just a 
plain old TNC interface. 

THS, written by Peter Heinhch HB9CVV, is 
a much fancier program, and I suspect that 
most people will want to run it as their terminal 
program. THS supports several windows for 
multiple sessions, a window for commands, a 
number of different buffers for capturing or 
sending information, and a file transfer mech- 
anism called YAPP (Yet Another Packet Pro- 
tocol). THS is about the nicest AX. 25 packet 
program I have used. I especially like the mul- 
tiple receive windows lor keeping sessions 
separate, as I sometimes run two or more 
QSOs at the same time. The full documenta- 
tion for THS is on the disk. 

Bulletin Board Operation 

BB, the second software package, is a very 
nice multi-connect bulletin board program 
written by Roy Engehausen AA4RE. This is 
the best bulletin board program I have used. 
The documentation is a little sketchy, but I 
found that I had no problems if\ very carefully 
followed the procedures outlined in the docu- 
mentation (contained in several files on the 
disk). 

BB is a full W0RLI/WA7MBL compatible 
BBS program with a very nice additional fea- 
tore: ft is multi-connect and multi-user. With 
BB running, several people can be connected 
to the BBS at the same time. Where I live, you 
can wait quite some time in the evening for a 
chance to log into the BBS to check your mail. 
BB even supports mail forwarding while users 
are on the BBS reading or sending mail. 

BB takes advantage of the background ser- 
vice provided by TNCTSR. If you are using 
BB, there is no need to run the big version of 
TNCTSR. BB runs in the foreground and pret- 
ty much takes over the PC, but I suspect that is 
neither unexpected nor a problem for anyone 
who already runs a BBS. 

I configured BB for one port and had my 
mail forwarded from the local BBS just so that I 
could see it in action. I also logged into and 
used BB from one of my portable packet sta- 
tions. I had the BBS up and running in about 
15 minutes. It performed flawlessly for the 
couple of days that I had it up. (Some people in 
the area even logged in and used the BBS.) 

As a result, I would not hesitate to recom- 
mend BB to anyone planning to set up a BBS. 
In fact, building a BBS around the PCPA and 
BB is probably the most cost effective way to 
get a BBS on the air. Not bad when the best 
performance also comes at the best price. 

22 73 Amateur Radio * October, 1989 



PC/Node 

NET/ROM by Software 2000 has become a 
very poputar tool for connecting different ar- 
eas of the world together into a packet radio 
network. The problem with NET/ROM and its 
clone TheNet {from Nord > < Link) is that they 
are ROMs that plug into a TNC. A TNC does 
not make a very good network node, and you 
need a separate TNC for each radio you want 
to connect. If you consider the cost for a two- 
port NET/ROM node and include power sup- 
ply, two TNCs, and two NET/ROMs, you will 
spend the better part of S500. For that price, 
you can get a PC. the PCPA, and this soft- 
ware. When it comes time to expand to more 
ports, PC/Node and an additional PCPA are 
much more cost effective. 

Unfortunately. I did not get a chance to try 
out PC/Node. I did read the documentation 
that came on the disk, however. Installation 
and configuration appeared to be quite clear 
and straightforward. 

TCP/IP 

The last software package that DRSI pro- 
vides with the PCPA is a version of Phil KanV s 
Net program. Net is a complete implementa- 
tion of the industry standard networking proto- 
col TCP/IP. as well as a full AX25 and NET/ 
ROM implementation. (There is even a 

WfcRLi /WA7MBL compatible BBS available to 
work with Net. but it was not available with the 
DRSI version at the time I tested the PCPA.) 

Net is more complex to operate than THS, 
but it provides much more flexibility. You can 
make connections via AX. 25, NET/ROM, and 
TCP/IP- The number of connections you can 
have concurrently are limitless. You can also 
do multiple file uploads or downloads. Imag- 
ine receiving and recording your mail from 
more than one BBS at the same time. 

The NET/ROM capability is nice to have. 
Other NET/ROMs think that your station Is 
another NET/ROM and can use your station to 
forward NET/ROM packets. With the PCPA, 
you can have several ports to provide cross- 
band and backbone linking. In terms of price, 
it is less expensive to construct a four-port 
NET/ROM Meganode using a PC and two 
PCPAs than it is to use four TNCs and four 
NET/ROMs. It also eliminates the need for the 
octopus cable to connect the TNCs together, 

Net really shines in running the Internet 
Protocol Suite (TCP/IP). Many protocols make 
up this suite, but a few are worth mentioning 
here. The first is Telnet, a terminal-to-host pro- 
tocol. Telnet is an official protocol specifica- 
tion for connecting a terminal to a host com- 
puter, in amateur radio. Telnet is used to carry 
on a keyboard-lo-keyboard QSO. 

The second protocol is the File Transfer 
Protocol (FTP). FTP provides both binary and 
ASCII file transfers. The ASCII mode performs 
alt character translations necessary for file 
compatibility with the destination host com- 
puter. Best of all. it is very efficient— a big win 
over programs like YAPP and BtoA. 

The third protocol, the Simple Mail Transfer 
Protocol (SMTP}, is an industry standard elec- 
tronic mail protocol (the W0RLI BBS supports 
SMTP messages, if I am not mistaken), Since 



it is a standard, it is compatible with mail sent 
by other non-ham computer systems. 

Net supports other connection modes be- 
sides packet radio, it can use inexpensive lo- 
cal area network cards to interconnect multi- 
ple computers. Net also supports RS-232 
connections for point-to-point or autodial con* 
n actions. 

I have used Net to connect all the comput- 
ers in my shack (only one of which is an MS- 
DOS computer). That way, I could access my 
computers from anywhere. I take my laptop 
computer with me and use TCP/IP to send 
mail, transfer files, or even run programs on 
the computers back home. Some of the con- 
nections use Ethernet and some use RS-232. 
The only difference is speed, which you can't 
even detect in most cases. 

The RS-232 connection makes another 
mode of packet operation possible: the 
"wormhole." Sometimes it is impossible to 
provide an RF link to connect two stations In 
such a case, you can substitute a telephone 
link to keep information flowing while the RF 
links are established or repaired. 

Since many companies, educational institu- 
tions, and governmental agencies use TCP/IP 
to connect their computer systems, it may be 
possible to use excess network capacity to 
give your packets a free ride. In one experi- 
ment, several hams using Net built a connec- 
tion between a shack and a remote host com* 
puter using five RF connections and about 
seven landfine and LAN connections. Seven 
computer networks were involved. It was 
amazing to see packets moving quickly and 
reliably between the ham's PC and the remote 
mainframe hundreds of miles away. 

The Future 

Lots of new software is becoming available 
for the PCPA because it is so easy to develop 
software on the PC. No ROMs, ROM burners, 
cross compilers, or special development sys- 
tems are required, This means that, unlike 
TNCs, there will be more and more software 
for the PCPA as time goes on. This translates 
into long life lor the PCPA, What capability you 
have today is only a fraction of what you will 
have tomorrow. Already the PCPA has been 
used to perform packet communications at 56 
Kbps using the WA4DSY modem. At those 
speeds, it could even be used for packet voice 
operation. 

Conclusion 

The PC 'Packet Adaptor is an excellent 
product; it is reliable and appears to be well* 
built. The software is nothing short of phenom- 
enal. Would I recommend it? You bet— with- 
out any reservations at alt. This is what packet 
radio was meant to be: powerful fast, effi- 
cient, and expandable. The PC 'Packet Adap- 
tor makes it worthwhile to get a PC just for 
packet radio operation. 



Brian Lloyd WBBRQN has pursued amateur 
radto enthusiastically since age etght. He re- 
cently co-founded Sinus Systems, a network- 
ing business in Petersburg. Vsrgima, You may 
reach Brian at: 5712 Stilfweit Rd.. Rockvitte 
MD 20851. 




Wmrffwk 



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73 Amateur Radio • October, 1989 23 



Number a on your Feedback card 



My SX-64 Runs Digicom! 

Low-cost packet solution for your portable C-64. 



by Ted Drude KA9ELV 



By now, most packet radio enthusiasts are 
probably aware of the excellent pub- 
Ik domain software TNC-2 emulator called 
Digicom > 64, which runs on Commo- 
dore C-64 computers, It was originally 
written by West German hams Stefan Eck- 
art DL2MDL and Florian Radleherr 
DL8MBT, (See Barry Kutner W2UP's 
article on Digicom in the August 1988 issue 
of 73.) 

Digicom is a great way of getting on packet 
radio, assuming you have a C-64 computer 
or a compatible system (C-64C, C-128, 
or C-I28D). You can use several types 
of inexpensive single chip modems with 
Digicom. Most can be built from scratch 
or from a kit for under $50. Version 2.0 of 
the program has many features not even 
found in hardware TNC-2s, including multi- 
connects, auto message store and forward, 
large text buffers, and many BBS-like func- 
tions. 

While C-64 users have been having a ball 
with Digicom, Commodore SX-64 owners 
have been left out in the cold, That is, until 
now! If you couldn't figure out how to get 
Digicom running on your SX-64 portable, 
you can get the complete story here, includ- 
ing how to modify Digicom modems to work 
with the SX-64, and how to make the proper 
internal connections. 

What Is An SX-64, Anyway? 

The SX-64, a portable version of the C-64, 
operates on AC power. It consists of a C-64 
compatible CPU, a 1541 disk drive, a five 
inch color monitor, and a built-in audio amp 
and speaker. All components are housed in a 
15 r ' x 16" x 5" metal case with a sturdy 
carrying handle. The detachable keyboard 
folds up over the screen and disk drive for 
easy t ran sportat io n \ 

The design of the SX-64, with its ample 
internal power supply and its huge cast- 
aluminum heat sink, makes it more durable 
than the C-64. And, unlike most C-64s, you 
can leave the SX-64 on for days, usually 
without the worry of overheating or other 
problems. 

Commodore originally sold the SX-64 for 
$995. When price wars drove the home com- 
puter market soft in 1983-1984, these 
machines were discontinued, and many were 
sold through surplus and liquidation chan- 

24 73 Amateur Radio * October, 1989 




Photo A. Tills SX-64 (left) is running Digi- 
com > 64 Version 2 JO with an internally 
mounted packet modem. External video mon- 
itor (right) displays incoming packets, with 
Digicom in monitor mode. 




© 




I/O Board 
CPU Boartf 



Figure L Commodore SX-64 (top view). 



IZ3 



] [ 



6510 



}i|M 1 1 

» UD7 



Figure 2. SX-64 CPU Board (component 
side). 




FigureS. SX-64 I/O Board (component side), 

















A 






w 




* 










< i!> v 








■ — I 















Figure 4. SX-64 CPU Board power connector 
(detail). 



nels. However, SX-64 repair parts are still 
available, and many SX-64s in good to excel- 
lent condition are currently available at 
hamfests and computer flea markets for 
$3O0-$50O. 

Why Won't Digicom Run on the SX-64? 

The SX-64 is virtually 300% software 
compatible with the C-64, but the hardware is 
a different story. Digicom is written to ad- 
dress a modem circuit connected to the 
C-64's cassette port. That's fine for C-64Cs, 
C^128s, or even C-128Ds, all of which have 
the nearly obsolete cassette port installed on 
them. But Commodore, in its infinite wis- 
dom, decided to put all C-64 I/O ports except 
for the L 'redundant" cassette port on the 
SX-64*s back panel. Almost all the internal 
circuitry needed for the cassette port, howev- 
er, it is still present inside the SX-64; it just 
isn't brought out to an external port. 

Get the Latest Release 

Digicom version L42 was originally writ- 
ten to overcome the missing cassette port 
problem since it addressed a modem connect- 
ed to the user port, which is present on the 
SX-64. However, this version of Digicom is 
much less powerful than versions 2.0 and 
later, as it lacks multi-connects, connect log- 
ging, store and forward, and so on. The actu- 
al release copies of version 1 .42 are buggy 
and poorly documented. 

I suggest you use the latest version (version 
2.10asof this writing). Besides, many SX-64 
owners already use the user ports for other 
things, such as telephone modems, RS-232 
ports, or, as I am doing, for home-brew Cen- 
tronics printer interfaces. The secret is in 
knowing how to make the right connections 
between a Digicom modem and the SX-64's 
internal chips. 

Installing the Modem 

Begin by removing the ribbed plastic trim 
panels on both sides of the computer. They* re 
held in place by four small screws, two on 
each side, in the middle of the back heat sink 
panel. After removing the screws, slide the 
panels out toward the rear of the computer. 

Next, remove the six countersunk machine 
screws, three on each side, that are holding 
the top cover in place. After that, remove the 
two large screws at the top corners of the back 




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Figure 5. Digicom modem modification for 
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Figure ft Digicom modem to SX-64 wiring 
diagram. 

heat sink panel and (carefully) loosen the two 
lower screws. This should let you remove the 
top cover of the SX-64. 

Looking down from the top of the open 
SX-64 (see Figure 1), you can identify 
the major components of the system. You*lt 
have to remove the CPU and I/O circuit 
boards, which are located on the right 
and connected in an inverted L shape. 
Before you can do this, you have to remove 
numerous cable connectors that hold the 
boards in place. Remove the boards as a 
unit; don't try to separate them inside the 
case. (A word to the wise; Mark the cable 
connectors to make sure you reconnect them 
correctly.) 

Identifying the Proper Connections 

With the CPU and I/O boards out, you'll 
want to identify the chips that connect to the 
Digicom modem. On the CPU board (see 
Figure 2) s find the 6510 microprocessor 
chip. it*s identified as UD7 on the board's 
silk-screened legend, Connect wires to pins 
24, 25, and 26 of this chip. 

Now see Figure 3. On the I/O board, 
find UB3, a 6526 CIA chip. It's the lower of 
the two 6526s on the I/O board. Connect a 
wire to pin 24. To Find the correct pins on 
either of these chips, it's faster to start count- 
ing from pin 21* the pin diagonally across 
from pin 1. 

If you're mounting the Digicom modem 
internally, you need to connect to the internal 
power supply. Fortunately, the SX-64 has 
enough surplus current to power most 
modems, The CPU board's power connector 
is a good place to get regulated voltage. This 
keyed 6™pin connector is at the lower left side 
of the CPU hoard (refer to Figure 2). Both 
+ 5 and + 12 volts are available, as well as 
ground (see Figure 4). 

Modifying the Digicom Modem 

W2UP T s article (mentioned earlier) 
presented a modem circuit capable of 
both HF and VHF packet operation using the 
AMD 7910 chip. Craig Rader N4PLK 

26 73 Amateur Radio * October, 1989 




Photo B. You can safely solder the leads ft om the Digicom modern (top) to the solder side of the 
SX-64 's CPU hoard (left) and I/O board (right), using a low wattage, grounded iron. Work 
patiently, use solder sparingly , and avoid bridges. 




Photo C. Here 's the modified N4PLK modem mounted to the SX-64 f s CPU and I/O hoards via a 
circuit board standoff (upper left corner of I/O board). Connections from modem to transceiver 
are made by using the external serial port pin socket, cable, and DIN connector. 



offered a simpler, more compact VHF-only 
modem using the TCM 3105 chip (see the 
February 1989 issue of 73). Other modem 
circuits, that have appeared in various 
forms, use the XR-2206/2211 chips. I 
chose the N4PLK modem for my project 
because of its small size and single supply 
source voltage* 

While all these modems work with the 
SX-64, they need a slight modification be- 
cause the cassette motor supply voltage on the 
C-64 cassette port, line number 3, isn't at 
TTL voltage levels. The cassette motor sup- 
ply voltage, controlled by a bit on the 6510 
I/O port, is switched through a transistor net- 
work to handle the current. The actual output 
level varies from to 9 volts, depending on 
current loads. 

Typically, a Digicom modem uses two 
I -2.2k resistors in series to act as a voltage 
divider for line 3 (see Figure 5). This brings 
the high voltage down to 3-4.5 volts, which is 
within TTL levels. To modify a Digicom 
modem for an SX-64, simply remove the 
resistor going to ground. The voltage divider 
network then becomes a single series resis- 
tor, which you can keep intact if the input line 
is directly driving a transistor. On the 
N4PLK modem, line 3 goes to a TTL level 
input, so I replaced the series resistor with a 
wire jumper, because the 65 1 I/O port lines 
are rated to drive only a single TTL level 
load. 



Making the Right Connections 

When you're ready to connect the modem 
to the SX-64, follow the wiring diagram in 
Figure 6. This gives the description of the 
internal modem line, the equivalent C-64 cas- 
sette port line number, and where the line 
should connect inside the SX-64, I removed 
the 6-position female edge connector (nor- 
mally used with the C-64 cassette port) from 
my modem, and ran jumper wires directly 
from the modem to the SX-64 circuit boards, 

I tried a variety of methods for tapping into 
the SX-64's circuit boards, including micro- 
clips and DIP sockets. The best method ap- 
pears to be soldering directly to the solder 
side of the boards, using a low power, 
grounded solder iron (sec Photo B), Work 
slowly, go sparingly on the solder, keep some 
desoldering braid handy, and watch out for 
solder bridges. 

Take note of one important connection not 
shown on the wiring diagram. Pin 24 of UB3 
also goes to pin 1 of the serial bus of the 
SX-64, For some reason, many C-64s must 
have pin 1 of the Serial Bus disconnected for 
Digicom to work properly. Some hardware 
interrupt conflicts appear to cause this prob- 
lem with certain serial bus devices (especially 
older disk drives, and printer interfaces). In 
any case, if you run into this problem, try 
disconnecting the black jumper wire from 
PI 1 to P13 on the I/O board. You can safely 



remove it without affecting any serial bus 
operations. 

Mounting the Modem and Tidying Up 

Before you connect the modem perm- 
anently, consider how you plan to mount 
it. F kept the modem completely internal 
and mounted it on the I/O board, using a 
circuit board standoff and insulator available 
from Radio Shack (see Photo C>. With 
the modem internally mounted and powered, 
you have to find a way to run the four ex- 
ternal lines to your transceiver (audio in, 
MiCOUT, PTT, and ground). You may decide 
to run a cable out of the cartridge expansion 
port, on top of the machine, or use a thin 
ribbon cable and ran it between the side 
panels. 



"White C-64 users 

have been having 

a haft with Digicom, 

Commodore SX-64 

owners have been 

left out in the cofd . . 

until now!" 



I wanted a cleaner approach, however, 
without having to drill any holes in either the 
SX-64 1 s case or its back panel, so I decided to 
use the external serial bus connector. (I didn't 
choose the external video port because I like 
to run a larger monitor on my SX-64 when 
Vm not operating portable.) By disconnect- 
ing the internal header connector from the 
I/O board and hooking the first four positions 
of it to the pin connector on my modem, I 
have a clean output port for my Digicom 
modem. The 6-pin DIN serial bus connector 
on the back panel now mates directly with a 
shielded cable running to my transceiver. 

Kudos 

Special thanks to Mike Hooper JCF6FU and 
Dan West K6DFM for their detailed infor- 
mation about Digicom and confirmation that 
it could run on an SX-64, to Jeff WA6FWI 
for the details on internal modem connec- 
tions, to Craig Rader N4SCY for help on 
modifying the Digicom modem for the SX- 
64. and to Robert 'Ozzicf ' Osband N4SCY 
for all the encouragement and moral support, 
as well as extensive testing of the completed 
system 



Ted Dntde KA9ELV has been a ham for 10 years, 
and especially enjoys packet and 10m Fhi, Ted is 
the Associate Editor of Computer Shopper 
magazine. Other interests include photography 
and computer games. You van reach Ted at: 6170 
Quito A ve. . Cocoa FL 3292 7. 




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73 Amateur Radio * October, 1989 27 



Number 9 on your feedback card 



Digital Dreams 

We have not yet begun to packet! 



by Bdale Garbee N3EUA 



DXers: Imagine a new operating mode 
that would let you work that last country 
for DXCC a little more easily, and with fan- 
tastic audio quality! What about a nationwide 
database to help you spot that elusive new 
country, in real time? Or a database with QSL 
information at your fingertips? 

ATVers: Imagine a national network of 
amateur High Definition TV (HDTV)— with 
image resolutions at least twice that of your 
broadcast TV images— with nearly perfect 
image transmission between any two places 
of your choice. 

Repeater trustees: Imagine a nationwide 
repeater linking system, with audio quality as 
good or better than what your local users are 
already accustomed to? How about if the 
snazziest repeater controller you've ever 
seen was included for free? 

Members of public service or emergency 
communications groups: Imagine how the 
people you serve would feel about being able 
to exchange 1000 times as much traffic 
throughout your state as is presently done, 
and with less effort, 

Computerniks: Imagine having enough 
space for all the neat applications you'd like 
to try out. Would you be interested in loading 
programs from a remote file server located 
across town, across the state, or even in an- 
other country . . .and running them just as if 
they were on your very own hard disk, and 
just as quickly? 

Special interest folks: Imagine sharing 
your interest(s) with others around the nation 
in an ongoing bulletin board forum just like 
those used on ARPANET, CompuServe, and 
other networks and online services. 

Packeteers: You probably think that you 
already know what Fm leading up to. But, 
even as a packeteer, you may not realize the 
potential of digital communications, using 
technologies already available. All of the 
above * 'fantasies* ■ are just a few of the neat 
things you could do if only you could move 
enough bits per second through a real packet 
network. The fact is, you can , and this article 
explains how! 

Move Up Frequency 

Look upward for the answer. Two meters, 
where most 1200 baud operation is today, is 
way too restrictive. There are several very 
simple reasons for that: 2 meters has become 

28 73 Amateur Radio • October, 1989 



very crowded, and, most important of all, it 
does not allow us the signal bandwtdths need- 
ed to run truly high-speed packet. (Recall that 
the higher the data rate, the wider the mini- 
mum bandwidth must be.) The ham mi- 
crowave bands, however, are still virtually 
deserted, and there are no signal bandwidth 
restrictions: You can have a signal many 
megahertz wide there if you want to! And yet 
to run packet at the truly awesome rate of 1 
Megabaud— 700-800 times the rate of the 



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mobile, repeaters, 

orGW, a nationwide 

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standard 1200 baud packet today— requires a 
signal bandwidth that could easily fit into 
many of the ham microwave bands. 

For higher speed operation, these bands 
actually work better than VHF or UHF be- 
cause small, highly directional antennas can 
allow our transmitted power to go much more 
where we want it to, wasting less of it in the 
wrong direction. Combined with the larger 
widths of the amateur microwave bands, this 
advantage allows efficient and affordable 
high-speed radio links* 

One of the lessons to be learned from the 
recent loss of part of the 220 MHz band is that 
the FCC may be increasingly concerned with 
the level of use in various portions of the 
amateur radio spectrum. If there are bands 
that we aren't using fully that commercial 
interests want, we'll have a hard time ratio- 
nalizing to the FCC why we should be 
allowed to keep spectrums we're not using. 
The answer is simple, and without pain. . . 
find ways to better use these bands! 

You may regard the world above a giga- 



hertz with some fear and suspicion. In reality, 
though, emerging microwave surplus and 
technology is quickly making it nearly as easy 
and cheap to build packet hardware for i.2 
GHz or 10 GHz as it is for 144 MHz. Several 
projects are underway right now that are 
opening the door to much higher speeds on 
bands at VHF and above. There is a standard- 
ized 9600 baud radio modem now available— 
a good 'next step 1 for many packet users. 
Hams in different parts of the country are 
using 56 kilobaud modems with conventional 
VHF/UHF transverters, with a good deal of 
success, on bands as far down as 1 .25 meters! 
Prototypes are being developed for dedicated 
"digital radios" for the 900 MHz and 1.2 
GHz amateur bands that can provide 250 
Kbps for a parts cost of under $200 per sys- 
tem. Dayton this year gave us demonstrations 
of dedicated digital radios for the 10 GHz 
band, using surplus radar gun modules to 
achieve between 1 and 10 Mbtts/sec, for un- 
der $100 per system! This sort of equipment, 
which is here now, can be put to use in 
providing high speed user-to-user and inter- 
regional digital communications. 

Building a Network 

We need to be able to efficiently direct 
packets from one user to another, with mini- 
mum hassle. Up to now, the technology ama- 
teurs used for building packet networks con- 
sisted mostly of TAPR TNC-2s and clones 
running replacement firmware to provide 
network functionality . While this was an ade- 
quate way to build 1200 baud networks, the 
Z80 microprocessor used in the TNC forced 
limitations in speed and software capacity 
that prevented us from building high speed 
networks. This is not surprising, since these 
are Terminal Node Controllers. They were 
never intended to be network packet switch- 
es! To build a fast network we need to look 
for higher performance solutions. 

Luckily, for about the price of a dual-port- 
ed configuration (that is, two TNC-2s, and 
two copies of some networking firmware) we 
will soon be able to buy a PS- 186 packet 
switch board from AEA that is based on an 
80C186 and which has 4 high-speed radio 
ports. Or, we could use the the K3MC card 
that will be available soon. This card is based 
on a NEC V40 (software compatible with the 
Intel processors) and has two or more medi- 



um-to-high-speed ports. Either of these 
boards is capable of switching multiple high 
speed channels, and can provide far more 
memory addressing capacity than Z80-based 
TNCs. 

Challenges Remain 

Having faster and more capable packet 
switching hardware, however, doesn't solve 
all of our problems, We'll need to work to- 
gether to solve specific local propagation 
problems for the hardware to work well, and 
we wilt need to agree upon and coordinate 
data routing at the "software" level so that 
the packets go quickly and directly to their 
destinations. These are, however, very man- 
ageable problems. 

One of the most important difficulties with 
existing 1200-baud packet networks is the 
large number of single-port network nodes, 
either simple digipeaters* or NET/ROM or 
ROSE nodes (two versions of a network sys- 
tem). When the network must contend with 
local users for access to the RF channel, the 
efficiency of a network can easily drop to 
near zero! The way around this? Install a 
"backbone 1 * channel— a high data rate chan- 
nel (e.g. 4800 or 9600 baud) that only the 
nodes of a packet system use, to automatical- 
ly route packets between each other. An end 
user^one who connects into the network- 
would not have direct access to the backbone. 
The highly successful TexNci packet net- 
work, for example uses 9600 baud backbone 
channels. We MUST further pursue the in- 
stallation of networking hardware with one or 
more channels dedicated entirely to back- 
bone* functionality, the communication be* 
iween packet switches. Local users can then 
use separate channels for access, at whatever 
speeds and using whatever frequencies and 
modulation techniques are appropriate in 
each area. 

A simple technique for making a dramatic 
improvement in local packet throughput is to 
make one or more of the local access channels 
full duplex— that is. having two channels in 
full-time operation so that the participating 
packet stations can transmit and receive 
simultaneously. This is exactly the same idea 
as using a repeater for voice. Everyone can 
hear everyone else, so the chance of two 
people transmitting at the same time and 
causing a collision goes way down, And it's 
no harder to build a full duplex digital re- 
peater than it is to build a voice repeater! Full 
duplex access channels are already in use in 
several packet networks around the country. 

Software 

Having faster modems and radios, howev- 
er, isn't enough. Once we've begun to build a 
real network of high-performance packet 
switches linked with fast microwave links, 
we will be ready to start experimenting with a 
wide array of new applications. The im- 
portance of having a solid software founda- 
tion, using proven networking concepts to 
provide a consistent and simple interface for 
writing new applications, will become more 
apparent. 

Fortunately, we're well on our way to 



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73 Amateur Radio * October, 1969 29 



M» 



developing the kind of software that can 
exploit these data rates. There *s already a 
host of networking systems which are being 
improved by the day (the five most popular 
systems are featured elsewhere in this issue). 
Today, among other features, software pro- 
vides electronic mail, remote log-in and key- 
board -to^key board QSO functionality, file 
transfer (including binary files) , and the abili- 
ty to obtain information about users in other 
areas. There's no limit to the applications that 
can be added. 

Immense Potential 

So, what's the bottom line? TNCs and 1200 
baud modems and keyboard-to-keyboard 
QSOs are not the sum and substance of 
"packet radio/" Recognize that what we've 
done so far in the name of packet radio is but 
the first small step towards what we are capa- 
ble of doing. A real digital network won't 
take away from the present interesting areas 
of amateur radio, . .it will add to them! 
Whether your interest is DX, rag-chewing, 



mobile, repeaters, or CW, a high data rate 
nationwide packet network supporting a vari- 
ety of applications can make ham radio even 
more fun for you . 



" P - - we should 

recognize that what 

we've done so far in the 

name of packet radio is 

but the first small step 

toward what we are 

capable of doing/' 



As mentioned above, very inexpensive 
links on 900 MHz, 1.2 GHz, and 10 GHz, 
with speeds from 250 kbps to 2 Mbps, have 
been tested on real paths in Colorado and in 



Silicon Valley. We will be seeing the first 
offerings in a new round of packet digital 
hardware with dramatically higher perform- 
ance than the TNCs of yesteryear. We will 
actually have the tools in hand to put a whole 
new wave of applications on the air. But 
while we 1 re busy implementing this next 
wave of packet radio, let us not forget to 
dream. The young but growing amateur radio 
digital network needs YOUR dreams and 
help. We've only just begun! 



Bdale Garbee N3EUA has long been involved in 
digital networking, but finally became a ham in 
1985 when he came across his first TNC. This 
began his intense affair with packer radio, which 
has led him to many achievements, including be- 
coming the system inte grater for packet radio s 
most sophisticated and versatile networking pack- 
age, TCP/IP, and becoming the Vice-President of 
the Tucson Amateur Packet Radio (TAPR) group * 
B dale currently writes oscilloscope firmware for 
Hewlett-Packard. Other interests include cooking 
and reading scien ce fiction . You may contact him at 
4390 Darr Circle, Colorado Springs , CO 80908. 



Number 1 2 on your Feedback card 



Let the TNC Work 
While Your PC Sleeps 

Give your older TNC personal mailbox capability- 

with no hardware changes! 



by David Bartholomew WB6WKB 



Many packeteers are using the older 
TAPR TNC-2 units, or their clones, 
manufactured by AEA, MFJ, and others. 
Unlike some of the newer models from 
Kantronics and Heath , these TNCs do not 
provide an automated "personal mailbox" 
feature to accept incoming messages. 

However, there *s a procedure that does this 
very well, and I've used it on the AEA PK~ 
80, the PK-232, and the MFJ- 1 270 TNCs. It 
will likely work with other models. This pro- 
cedure isn't in any TNC manuals I've seen. 

Turn Your Packet Answering Machine On 

First, turn off ail the monitors with mon 
off and mcon off. (On the PK-232, use mon 
and mcon o.) Set up your ctext to say 
whatever you want. I usually say something 
like T "Dave's not in, please leave a message 
here or at WB6YMH-2. . .73." Make sure 
CMSG is ON. Also, if it's not already set on 
your TNC, set DAYTIME, then CON5TAMPON 
and daystamp on, too. This will let you 
know when people contacted you. 

30 73 Amateur Radio • October, 1989 



Now type in day, press Ctrl-S, and type 
ENTER. This "suspends" the TNCs out- 
put. Now disconnect the RS-232 cable from 
your computer or terminal, and turn it off, 
but leave the TNC and radio on. This allows 
you to use your computer for other things 
while your TNC acts like a packet answering 
machine for you. 

The TNCs Tve tried have buffers of 3K or 
more (depending on the software version). In 
most cases, this is adequate for several con- 
nects. On connecting, a person can leave a 
short message for you, and when their sta 
(status) light goes out, they can disconnect. 

I disconnect the RS-232 from the computer 
because sometimes the computer will send a 
pulse out the interface during power up. This 
might trigger a Ctrl-Q, and the contents 
of your TNC would go straight into the bit 
bucket, 

Therefore, follow this procedure to check 
your TNC when you come back: Power up 
the computer and go into your terminal pro- 
gram. Set up a "capture file" to disk, or turn 



your printer on and enable printing. Now 
reconnect your RS-232 cable, and press Ctrl- 
Q. Everything should come spilling out of the 
TNC, (You may also have to press Ctrl-C 
before it will start.) 

The first thing out is the date and time that 
you suspended your TNC, (We did this oper- 
ation so that, if nobody connected, all we got 
was the date and time.) If you do not get this, 
youTl know that the buffer was lost. This 
could be due to a glitch on the interface, as 
mentioned, or a power surge. 

If you don't like plugging and unplugging 
your RS-232 cable, buy a serial switchbox. I 
have mine connected to switch between my 
PK-232 and my phone modem, This saves 
wear and tear on the connectors, and 1 don't 
have to reach behind the equipment. 



David WB6WKB has been a ham since 1977 and 
active in packet for several years, A software de- 
signer, his other interests include hiking, stargaz- 
ing, desert geology, and plants. His address is PO 
Box 7883, Van Nuvs CA 91409-7883. 



Number f on your Feedback card 



Put Your IC-22S on Packet 

Dust it off and dedicate it to 2m packet! 

by Michael S. Dooley KE4PC 



Are you tired of tying up your synthe- 
sized radio on packet? If you have ac- 
cess to an ICOM IC-22S, a fast and easy fix 
will get it on this fascinating mode. 

With the help of the schematic, find the 
Reference Oscillator/Divider. This is a 7,68 
MHz crystal. Replace that with a 5. 12 MHz 
crystal. This lets you tune the 22S in 10 kHz 
steps. 

The crystal is available through several ad- 
vertisers I've seen in computer magazines, as 
well as from any of the crystal manufactur- 
ers. I got mine from International Crystal in 
Oklahoma City . If you order from a manufac- 
turer, include the loading capacitance . Send 
them a copy of the IC-22S schematic, and the 
manufacturer will figure out the loading for 
you. (I didn't know what the loading was, and 
so asked for a 20 pF one, which works fine.) 

Now just follow the Table to configure the 
diodes for the packet frequencies on which 
you want to operate. That's it! 

Drawback? 

The only problem is that, with the new 







Table of Diode Settings for the IC-22S 






Frequency 


D7 




D6 


D5 


D4 


D3 


D2 


01 


DO 


145.00 










1 


1 


1 


1 





1 


145.01 










1 


1 


1 


1 


1 





145.02 










1 


1 


1 


1 


1 


1 


145,03 







1 




















145.04 







1 

















1 


14505 







1 














1 





145.06 







1 














1 


1 


145.07 







1 











1 








145.08 







1 











1 





1 


14609 







1 











1 


1 





1 145.10 







1 











1 


1 


1 


(0 = diode not installed; 


1 =< 


jiode installed) 













crystal* the ICM2S works only from just be- 
low 145 MHz to 146.94 MHz, and the offset 
function gives only a definitely non-standard 
±400 kHz split. But, what the heck!— this rig 
was likely busy taking up space on a shelf, 
while you were tying up a perfectly good 
synthesized split operation rig on packet, I set 



my channels as 145-01 MHz on channel one, 
145.02 MHz on channel two, 145,03 on 

channel three, and so on- Works great! 



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Number 19 on your Feedback card 



KAMBox 

Packet and WEFAX for the lazy, 



by Joe Davidson N4AQG 



I recently bought a 
Kanironics KAM 
Cor the shack. I had 
owned a Kanironics 
UTU and liked their 
product, so when 
ihe Vpacket-bug* 
munched on my ham- 
ming spirit [ went for 
the KAM. With the 
KAM I have been able 
to keep all my favorite 
modes , plus enter into 
the new worlds of 
packet and WEFAX. 

Most of my projects 
around the shack are 
driven by the desire to 
reduce excess motion 
or effort. This project 
is no exception. If ne- 
cessity is the mother of 
invention, then lazi- 
ness is its father. I 
have a good share of the 




PhoioA. From panel. 



Ml 



VMf M f VMF 

AUDIO 



JM PIT J^ PTT A OUT djfc 



IN 



OUT 




HF 





latter. 



Alterations for the Lazy 

To copy WEFAX, I had to unplug the 
HF audio from the HF port and plug it into 
the VHF port. Then I decided I'd like to work 
the local VHF RTTY repeater. Kantronics 
routes the RTTY AFSK through the HF port, 
Hmmmmm, 1 couW swap the audio ports, but 
what about the AFSK and PTT? Little 
idea-gremlins began to scum around the back 
of my mind. 

I 1 vc built several switch boxes in the past so 
t knew that there w ? as a way around this prob- 
lem. Out came the paper and pencil, and the 
drawing began. Figure 1 shows the result. 

As J drew, a few ideas bobbed to the sur- 
face. I use the phone patch input on my FT- 
767 GX to input the KAM HF port transmit 
audio. At a recent hamfest, I bought a used 
Telex boom mike headset. Why not find a 
way to use it? Thus, the four-pin mike con- 
nector, the remote PTT jack, and the x MIT/ 
REC switch on the front panel. 

This box allows me to switch the HF audio 
alone to the KAM VHF port for WEFAX. It 
will also reverse the HF and VHF audio, 
AFSK and PTT to output RTTY on VHF. 
With a Hip of a switch I can use the Telex 
headset on HF for contesting, DXing, or just 
plain old gabbing. 

32 73 Amateur Radio * October. 1989 



Photo B, Back panel. 

Drilling the Connector and Switch Holes 

As the parts list reflects* you can buy al- 
most all the parts at your local Radio Shack 
store. 

I chose the cabinet because it would fit into 
the shack in a minimum of space* and because 
it had a clean, professional look. Plus t I want- 
ed the shielding properties of a metal case. 
This particular case has a nice addition — plas- 
tic film on the outer surface of both halves. 



"If necessity is the 

mother of invention, 

then laziness is 

its father/' 



This allows you to center punch and drill 
holes without scratching the surface. You can 
then peel the film off and label your box on a 
clean, unscathed surface, 

I measured and centered the hole locations 
for the switches and jacks on both panels. 
Then 1 cut a wooden block from a scrap 
two-by-four to fit snugly between the front 



and back panels. This 
block will support 
the panels so they 
won't bend when 
punching or drilling. 
Moving the block un- 
der each location be- 
fore drilling reduces 
the lip-burr formed by 
the bit on the inside of 
the hole, 

I center-punched the 
drill points and drilled 

firstwithal/8"drill.I 

used progressively 
larger bits until the 
opening was large 
enough for the collar 
of the switch or con- 
nector to fit through, 

To make the DB-9 
connector openings, I 
used a different 
method. First 1 drew 
an outline around one 
of the connectors at the desired location, then 
drilled a 1/8" hole in the center of the marked 
opening. Then I enlarged this hole in two or 
three stages to Va" . Among the tools on my 
workbench is a piece of magic called a iL nib- 
bler*'— small shears that let you accurately 
make your holes. 

I chose the DB-9 connectors for several 
reasons — they have good shielding proper- 
ties, and are becoming the connector of 
choice for serial ports. 

Label Pressing and 
Lacquering 

The next step was to dig out the sheets of 
dry transfer letters 1 bought from an electron- 
ic supply house. I used these to label the 
switch and connector positions. The package 
of letters contained several preformed elec- 
tronic terms, as well as an abundance of let- 
ters for composing your own. If you can't 
find these letter sheets at an electric supply 
house, office supply and art supply stores 
carry dry transfer letters in several sizes. You 
might warn to experiment with them a little on 
a piece of white paper. Make sure there is a 
hard surface under the paper. Rub over the 
letters several times with a wooden stick. (A 
pencil-shaped orangewood stick came with 
my sheets.) Then peel the backing away. 

Com i fitted on page 46 




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Come to Barry's for the best buys in town. 



ONV Safety 
belts in stock 



May We Help You With the Beat In Commercial and 
Amateur Radios? Lew W2BIE, Toni. Kitty WA2BAP. 
and JanKBZftV. 

SEE You Oct. 1 Sill— MOS ARC, Oyeens., NY 







r n 



<~ r> 



ICOM 

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CIRCLE 41 ON READER SERVICE CARD 



Number 11 on your Feedback card 



One-Chip RS-232 

for the C-64 

Easy and inexpensive RS-232/TTL level interface. 



by Mike Kabala KB0CDQ 



I was bitten by the computer bug long 
before becoming involved with ham ra- 
dio. Consequently, after I got my license, I 
was determined to find ways to combine these 
two interests. Noticing that many hams used 
Commodore 64s as packet terminals, log- 
gers, Morse code tutors, and several other 
things, I decided to put mine to good use and 
connect it to some of my other equipment. I 
wanted to use the computer's serial port since 
that would allow me to connect it to modems, 
printers, packet TNCs, and anything else 
with an RS-232 serial perl. 

But What Is RS-232? 

RS-232 is a standard for connecting digital 
devices together so they can communicate 
with each other. It was adopted by the Elec- 
tronics Industries Association (EIA) to make 
it easier to connect devices made by different 
manufacturers. The standard defines 25 sig- 
nals that can be used to establish a protocol 
between the devices connected. Most equip- 
ment uses only a few of these signals. The 
IBM PC-AT, for example, uses nine, which 
are attached to a nine-pin connector instead of 
the traditional 25-pin connector. 

When Commodore introduced the C-64 
home computer, ihe company included the 
same nine signal lines on the computer's seri- 
al port. As many owners already know, how- 
ever, hooking up the C-64 to another device 
with an RS-232 port is more involved than 
simply connecting a cable between the two. 
While the Commodore's signals agree with 
those defined in the EI A standard, the electri- 
cal properties of those signals do not. Com- 
modore's signals are TTL level signals, 
which means thai a signal of V to +0.8 V 
represents a Logic zero, and a signal of +2*4 
V to +5 V represents a logic one. The RS- 
232 standard, on the other hand, represents a 
zero with a signal of r3 V to +25 V and a 
one with a signal of —3 V to -25 V, 

To make matters worse, the only DC 
voltages present on the Commodore 64*s user 
port connector (the one containing the TTL 
level signals) are ground and +5 V. The chip 
normally used to convert TTL level outputs 
to RS-232 level outputs is the MC1488, but 
this chip needs both positive and negative 
power supply voltages to work properly. 

What I set out to do, then . was to find a way 
to convert all of the Commodore's signals 
from TTL level to levels that agree with the 
EIA standard. Furthermore, 1 wanted to do 

34 73 Amateur Radio • October, 1989 



this using as few components as possible. 
After asking around a bit, I heard that a com- 
pany called Maxim Integrated Products made 
some chips that operate off of a single +5 V 
supply. In fact, one of them, the MAX232, is 
used in Heath's Pocket Packet TNC- 

While most of these chips require external 
capacitors, the MAX235 docs not. Further- 
more, the MAX235 has drivers for five out- 
puts and receivers for five inputs. Since the 
Commodore 64 has three outputs and five 
inputs at its serial port, 1 realized that I 
could build the entire interface with only 
one chip? 







■hhh _; 


' " f 

11*231 MINI-TESTER 


TO 


^ 


^ RO 


RTS 
DSF 


) 


CIS 


cc 


1 


*DTR 



circuit shown in Figure 1 simply connects 
inputs to line receivers, outputs to line driv- 
ers, and +5 V and ground to ihe chip's power 
supply pins. 

The MAX235 chip also contains an enable 
pin and a shutdown pin. The enable line is 
active low (a TTL zero signal enables the 
chip), so it has been connected to ground, 
permanently enabling the outputs of the line 
drivers. A TTL one level signal on the shut- 
down pin causes the chip to go into a low- 
power mode when not in use to save power in 
battery-powered applications. Since this is of 
no concern in this project, shutdown has been 



An RS-232 mini-tester is plugged into the RS-232 port for testing. 



Theory of Operation 

The MAX235 uses 
two on-chip charge 
pump voltage conveners 
to transform the +5 V 
power supply into +10 
Vand -10 V, The +10 

V and —10 V supplies 
are then used by the 
chip's five line drivers to 
convert the TTL level in- 
puts to +10 V and -10 

V RS-232 signals. The 
receivers use the +5 V 
supply to convert RS- 
232 level signals back in- 
to TTL level signals . The 



TiitiiBLl [tot* 041 

Ur*|uri1 to \t-nd III 

Wminal fEmttu ID 

4B£I 

IE) 

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171 



Z34* 



vu 



in 






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Kram Data Q> 



Dear to Vnd Q 



Data 5*t ***** Ifi) 



Data CajTfcx Datart ill 



HiFvg InllcaL&r ilJi 



Figure L MAX235 IC inputs and outputs, 



disabled by connecting it to ground 

Construction 

This project is a snap to build, especially if 
you Need the following tips. 

After etching the board, use the four crop 
marks on the corners as a guide for trimming 
it I used a razor saw to trim mine. While the 
width isn't that critical, the front and rear 
edges of the board could interfere with the 
connectors if not properly trimmed. Take 
care, though, when trimming the edge closest 
to the DB25 connector: the traces come very 
close to this edge. 

If your male DB25 connector has mounting 
holes, by all means use them. If, like me, you 
arc constantly joining things and then taking 
them apart, this connector and the card-edge 
connector suffers a lot of wear and tear. Even 
if the installation is permanent, normal use 
can still strain the connectors. Over time, 
mechanical stress applied directly to the sol- 
der connections will cause them to separate. 

The part of the board on which the card- 
edge connector is attached has been designed 
for maximum flexibility in choosing a con- 
nector. It must, of course, contain two rows 
of 12 contacts of 0. 156-inch centers, but the 
solder side of the connector can be either the 
right-angle type or one with straight contacts. 
The right-angle type is better, since you can 
bolt them directly to the board, adding to its 
durability. For this, I provided two sets of 
hole patterns, one for 0. 150-inch spacing be- 
tween rows and the other for 0, 20CMnch spac- 
ing. Use the set thai matches your connector 
and ignore the extra row of holes. If possible, 
drill mounting holes for bolting the connector 
to the board. 

If your connector has straight solder tails, 
place the board between rows of contacts and 
solder the side touching the copper into place. 
You will have to drill holes and attach 
jumpers to reach the other row of contacts. 
Only three of these are needed— K 2. and 
12— since the other pads have no leads at- 
tached to them. 

I recommend using a socket for the 
MAX235 chip, With it. its easier to check 
for snider bridges before inserting the chip, 
Be sure that the chip is oriented correctly, so 
as not to damage it when applying power. 

The two jumpers are optional. They con- 
nect pin one (protective ground) of the DB25 
connector to pin seven (signal ground). Occa- 
sionally* these need to be tied together, 
(Again, I have never known this to be the 
case* but it might occur in the future.} Solder 
a wire between ihe two terminals of JP2. The 
terminals of JP1 are on .10-inch centers so 
that a removable jumper plug can be inserted. 
Solder two jumper pins to these holes. 

I rsting and Using the Device 

Once you have soldered all components 
into place, attach a jumper plug at JP1 . If you 
arc using a socket, leave the chip out for now. 
Check for a solder bridge across the power 
suppl) by connecting an ohmmeier between 
pins one and two of the card -edge connector. 
In a similar manner, check for bridges be- 
tween the pins of the card-edge connector. 















Jl 








ID7 — 




m\B 


MPl 




M* 








) 


Ul 








Figure 2. Interface component layout. 



between the pins of the DB25 connector, and 
between pins of the chip socket. There should 
be a short between pins one and A, pins 12 

and N, and pins L and M of the card-edge 
connector. There should also be a short be* 
tween pins 2 1 and 22 of the chip socket. No 
other shorn should exist between any two 
pins of the same connector. 

When you have removed all solder bridges, 
insert the MAX235 into the socket, taking 
care to observe the proper orientation. Make 
sure that all pins are in the socket and that 
no pins are bent under the chip. Next, insert 
the card-edge connector into the user pen of 
your Commodore 64 with the chip facing up. 
Plug an RS-232 mini-tester (available at Ra- 
dio Shack) into the DB25 connector if you 
have one. 




Now that , 

you can speak, 
talktoLarsen. 

Novice Enhancement opens up a 
whole new way for novices to com- 
municate. To make the most of it, talk 
to Larsen Electronics. 

We'll tell you how Larsen antennas 
can greatly improve your powers of 
communication. We'll also explain 
how Larsen 220 and 1296 MHz 
antennas are designed to give you 
the best performance. 

Talk to your Larsen amateur dealer 
today, and see if Larsen performance 
doesn't speak for itself. 





Larsen Antennas 

The Amateur's Professional 

See your favorite amateur dealer or write for a free amateur catalog. 

IN USA: Laisen Electronics, inc.. 11G11 ALE. SOlti Aw.. P0 Box 1799, vfricauvur, WA 98668. 206-573-2722. 
IN CANADA: Canadian Larsen Electronics, Ltd.. 149 West 6th Avenue, Vancouver. B.C. V5Y 1K3. 604-872-8517 



CIRCLE 23 ON READER SERVICE CARD 



73 Amateur Radio • October, 1989 35 



Official 1934 

SHORT WAVE 

RADIO MANUAL 




Build 

simple, high- 
performance old- 
time shortwave radios! 

Ail of the secrets are 
here: the circuit diagrams, 
parts layout, coil specifications, con- 
struction details, operation hints, and 
much more! 

This is a compilation of shortwave 
construction articles from "Shon Wave 
Craft' magazines published in the 20"s& 
3G's. It's wall-to-wall "how-to." 

Included are circuit diagrams, photo- 
graph s. and design secrets of all short- 
wave receivers being manufactured in 
1934 including some of the most fa- 
mous: SW-3, the SW-5 ~nirfll Box", the 
deForest KR-1, the Hammurland 
"Comet Pro", and many more. 

Also included is a new chapter show- 
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even see the circuit ihat was lashed 
together on a table top one night using 
junk box parts, a hair curler and alliga- 
tor clips. Attached to an an- 
tenna strung across the base- 
ment ceiling and a 9 volt bat 
tery. signals started popping 
in "like crazy. In a couple of 
minutes an urgent message 
from a ship's captain off Se- 
attle over 1500 miles away 
was heard asking for a naviga- 
tor to help htm through shallow watert 

These small regenerative receivers 
are extremely simple, but do they ever 
perform! This is a must book for the 
experimenter, the survival! st who is 
concerned about basic communication, 
shortwave listeners, ham radio opera- 
tors who collect old receivers, and just 
about anyone interested in old-time 
radio. 

Great book! Fun to read! One of the 
best old-time radio books to turn up in 
years. Heavily illustrated! Order a copy 
today! 8 1/2 x 11 paperback 260 pages 
only $15,70 postpaid! 

r Lindsay Publications 1 

Box 12-WG6, Bradley IL 60915 




1 Send a copy of Short Wave Radio 
Manual Enclosed is SI 5.70, 
Chk, MC, Visa, Send a free cata- 
log of other books. 



Mamr 



Address 



I 



St 



_Zip 



I 
I 
I 
I 
I 
I 
I 
J 




Figure 3. PC hoard foil diagram for the interface. Not a lot of 
pari stuffing here! 





Parts List 




Part 


Description 


Cost 


U1 


MAX235 R&232 driver/receiver 


$25.00 


(Ul) 


Socket (of Ul 


$ r00 


Jl 


Male DB25 with rigru-angle Header 


$ 4,00 


J2 


Card-edge connector 
12-positkm dual-readout 
on 156 mil centers 


$ 3.50 


— 


Printed circuit board (etched) 


$10,00 


JP1 


Removable jumper 


$ ,50 


JP2 


Wire jumper 


$ .01 


** 


Solder and mounting hardware 


$ 1.00 


MAXIMUM total cost (assumrng NO junk-bo* parts): 


$45.01 



THE RF CONNECTION 

"SPECIALIST IN RF CONNECTORS AND COAX" 



Part No. 

PL-259/USA 

B3-1SP-1Q50 

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PL259/ST 

UG-175 

UG-176 

UG-21DW 
U&21B/U 
9913/PIN 

U6-21D/9913 
UGr2 16/3913 
UG446WU 
UG-83BW 



Description Prlc* 

UHF Mate Phenolic, USA made $ ,70 

PL-259 Phenolic, Amphenoi 89 

PL 2 59 Teflon, Am pftcnul 1 7 5 

UHF Male Silver Teflon, USA 3 ,50 

Reducer for RG-58 .20 

ReducertorRG-59& MINIS ,20 

N Male RG 8, 213, 214, Polta 325 

N Male RG-8, 213, 214. Kings 5-00 
U Male Pin for 99 U. 90B6, S2 14 

fits UG<2 1 D/U & UG-2 1 BW N'l l 5Q 

NM3lerorRG-Bwi(h99l3Pln 3-95 

N Mai e for RG~B with 99 1 3 Pm 5.75 

H Male to SO 239, Teflon USA 6.00 

N Female to PL-259. Teflon USA 6.00 



"THIS LIST REPRESENTS ONLY A 
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CIRCLE 1 1 5 ON READER SERVICE CARD 




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call toll free 




1 -800-274-6754 



CIRCLE 27? ON READER SERVICE CARD 



Apply power to the Commodore 
64 and observe the mini-tester. The 
TD, RTS, and DTR indicators 
should be lit, AH others should be 
off. Tf you do not have a mini-tester, 
place the ground lead of a DC volt- 
meter on pin seven of the DB25 and 
check for a voltage of about + 10 V at 
pins two, four, and 20, 

Now, turn off the Commodore 64 1 
attach the mini-tester to the device 
you wish to conned to the computer, 
and apply power to the device. If the 
RD indicator lights and TD. RTS, 
and DTR remain off, you can proba- 
bly connect the Commodore to the 
device with a straight RS-232 cable. 
[f RD remains off and TD comes on. 
you will need a null-modem. RD is 
on pin three of the DB25 connector. 
There are many types of null- 
modems in common use, so consult 
the manual for the device to be con- 
nected to determine which type you 
need. If there is more than one dia- 
gram, use the one shown for an IBM 
PC. 

Now turn off both the computer 
and the device and connect them via 
their serial ports. Turn on the dc\ ice 
and the computer, as indicated in the 
device manual , and attempt to send 
and receive data between the two ma- 
chines. (If you are attaching a print- 
er, try sending data only.) You 
should be able to get your new port 
working without too much trouble by 
following the instructions in the manual- 
Summary 

I have built three of these interfaces so 
far. The first one was installed inside a 
Commodore 64 and brought out to an 
IBM PC-AT style DB9 connector at- 
tached to the side of the computer. I have 
used it, at various times, to attach the 
computer to a packet TNC, to an IBM 
PC, and even to an Apple LaserWriter 
printer running at 9600 baud. (Yes, the 
plural of baud is baud!) The second one 
is being used by a friend to connect his 
Commodore 128 computer to his laser 
printer. I keep the third one on hand for 
use with my Commodore 64C. I have 
had no problems with any of these inter- 
faces, and they are very easy to build, so 
warm up that soldering iron! 

About Parts 

There's just one hitch: I have checked 
several sources and have not yet found 
anyone interested in providing the 
MAX235 chip in single unit quantities. 
It is possible to get ten or more, howev- 
er. Assuming at least ten people will 
want to build this project, I will make the 
chips available for $25 each. I will also 
supply pre-etched circuit boards for S10 
each and complete kits for $50. Send a 
check or money order in U.S. funds to 
Mike Kobate KBQCDQ. 144 W. Spring 
Street, Eldridge, IA 52748 



36 73 Amateur Radio * October, 1989 




HF Equipment Regular SALE 

IC-765 Xcvr/ps/keyer/auto tuner 3149.00 2699 



_> ^ ^ o ^ (*5 . f** 



O © § ff r -£ 



ft ^> 



■iWtr' #*. 



i *ti *if- *■:■ &V-IZ3 



IC-781 Xcvr/Rcvr/ps/tuner/scope 



6149.00 5295 



..r y 



r *t Ua «f—i*. 3^ If : w^s**«i 



'.-"■■**S-*"ft"i . *-!v-- 



^TriiKAB: •.v.if*M8! 



\Ta^tS m ■) "^ 



IC-751A 9-band xcvr/.I-30 MHz rcvr 

PS-35 Internal power supply 

FL-63A 250 Hz CW filter (1st IF) 

FL-52A 500 Hz CW filter (2nd IF).... 
FL53A 250 Hz CW filter (2nd IF).... 

FL-33 AM filter , 

FL-70 2.8 kHz wide SSB filter..,,.... 
RC-10 External frequency controller 

IC-735 HF transceiver/SW rcur/mic, 
PS-55 External power supply .. t .. ; .. 
AT- 150 Auto, antenna tuner (Spetkt) 

FL-32A 500 Hz CW filter.,, 

EX-243 Electron ic keyer unit ..* 

UT-30 Tone encoder 



1699.00 1469 
219.00 199 95 

59.00 

115.00 109 95 
115.00 109 95 

49.00 

59.00 

49.00 

1149.00 999 95 
219.00 199** 
445,00 369 95 

69.00 
64.50 
18.50 




IC 725 Ultra compact HF xcvr/SW rcvr 949 00 829 95 
Other Accessories Regular SALE 

IC-2KL HF solid state amp w/ps 1999.00 1699 

IC-4KL HF1KW outs/samp w/ps 6995,00 5999 

EX-627 HF auto, ant. selector (Special) 315,00 269^ 
PS- 15 20A external power supply ...... 175.00 159^ 

PS-30 Systems p/s w/cord, 6-pin plug 349.00 319^ 
MB Mobile mount, 735/751A/761A.... 25.99 

SP-3 External speaker „., 65.00 

SP-7 Small external speaker 5199 

CR-64 High stab. ref. xtai for 751 A 79.00 

??4 Speaker/patch 17900 164" 

SM-6 Desk microphone...... 47.95 

SM-8 Desk mic - two cables, Scan 89.00 

SUMO Compressor/graph EQ r 8 pin mic 149.00 I39 95 
AM0O 100W 8-band auto. ant. tuner... 445.00 389 95 
AT-500 500W 9 band auto. ant. tuner ... 589.00 519" 

AH-2 8-band tuner w/mcunt & whip 758.00 689" 

AH-2A Antenna tuner system, onJy 559.00 499" 

GC-5 World clock fipeekl) ♦■ 9L95 69 w 

Accessories for IC-765, 781. 725 - CALL for Prices 



ICOM 



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VHF/UHF base mutti-modes Regular 

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IC-275H lQGw2mFM/SSB/CW..„.... 1399 00 

IC-375A 25 w 220 FM/SSB (Clmoui) 1399.00 

IC-475A 25w 440 FM/SSB/CW w/ps 1399.00 

IC-475H 75w 440 FM/SSB/CW. , 1599,00 

IC-575A 25w6/lOmxcvr/ps@^M0 1399.00 

IC-575H 100w6/10m mi 1699.00 

VHF/UHF/1.2 GHz Mobiles 
IC-47A 25w440 FM/TTP mic (Ckmat) 

PS-45 Compact 8A power supply.... 

UT-16/EX-388 Voice synthesizer.... 

SP-10 Slim-line external speaker.... 

IC-28A 25w 2m FM, HP mic (Speekt) 

IC-28H 45w 2m FM, TTP mic 

IC-38A 25w 220 FM, TTP mic .,.. 

IC-48A 25 w 440-450 FM, TTP mrc 

HM-14 Extra TTP microphone 

UT-28 Digital code squelch 

UT-29 Tone squelch decoder .. 

HM-16 Speaker/microphone .,. 

IC-228A 25w 2m FM/TTP mic (Special) 
IC-228H 45w 2m FM/TTP scan mrc... 

IC448A 25w 440 FM/TTP mic 

UT-40 Pocket beep function .. 

IC-900A Transceiver controller 



SALE 
1099 
1199 
799" 
1199 
1369 
1129 
1499 



Regular SALE 
549.00 369" 
145.00 134^ 
34.99 

469.00 379" 
499.00 439" 
489.00 349" 
509.00 449" 

59.00 
39,50 

46.00 
34,00 

509.00 429" 
539.00 479** 
509.00 449" 

45.00 

639.00 569" 



• Glomvt Special . , - 

IC-900A Transceiver controller with UX-29H 
2m/25W and UX-39A 220/25W band units. 

Package Price • $949 95 



UX-I9A 10m lOw band unit, 

U%29A 2m 25w band unit..... 

UX-29H 2m 45w band unit 

UX-39A 220MHz 25W band unit,... 

UX-59A 6m lOw unit 

UX-129A l.2GHz lOWband unit.... 

IC-901 Fiber Optic 2m/440 xm ...... 

IC-1200A lOw 1.2GHz FM mobile.. 

IC-250OA 440/ 1200MHz FM mobile 

IC-3210A 25w2m/440 FM/TTP.. 

IC-240GA 45w 2m/35w 440 FM/TTP 
AH-32 2m/440 Dual Band antenna..,. 

AHB-32 Trunk lip mount... 

larsen PO-K Roof mount....... , 

Larsen PO-TLM Trunk-lip mount 

Larsen PO-MM Magnetic mount 

RP-151G 25w 2m repeater 

RP-2210 220MHz 25w rptrffy&wj)... 
RP-1210 1.2GHz lOw 99 ch FM rptr. 



299,00 

299.00 
349.00 
349.00 
349.00 
549.00 



269 95 
269 9& 
319 9& 
299 95 
319" 
499" 



1199.00 1069 
69£O0 599" 
999.00 869" 
739,00 649" 
899.00 789" 

39.00 

35.00 

23.00 

24.70 

24.70 
1849.00 1649 
1549.00 1399 
1529.00 1349 



Due to the sire of the ICOM product line, some accessory 
Items are not listed. If you have a question, please call. All 
prices shown are subject to change without notice. 



Tap Trades ! • We'll take your 
Clean Late Model gear in trade 
towards New ICOM Equipment. 

Write or Call for our Quote Today! 
i® * Om $2 t$m in Amtew R$dio 




USE 

YOUR 

CREDIT 

CARD 

Hand-helds 
JC-2A 2-meters... 



VISA' 



Regular SALE 

..„. 289.00 259* 

IC-2AT 2m/TTP 319.00 279" 

JC-OZAT/High Power 409.00 349" 

IC-04AT 440 HT 449,00 389" 

IC-u2AT 2m (SpuM) 329.00 279" 



Extra Battery! . . . 
BP-23 600ma/8.4V • NO CHARGE 
with purchase of IC-u2AT 



HCTP5 



Mm! 

IC-2SA 
2m HT 



IC-u4AT MQ(Ch$mt) 

IC-2SA 2m HT. 

IC-2SAT 2mHT/TTP... 

IC-3SAT 220 HT/TTP 

IC4SAT 440 HT/TTP 

IC-2GAT 2m HT/TTP 

IMGAT 440MH; P TTP 

Speckf . . 

IC-32AT 2rn/440 HT 



369.00 

^19.00 
439,00 

449.00 
449.00 
429.00 
449.00 



199" 

369" 
389" 

399" 
399" 
379" 
399" 



629.00 549" 



IC-12AT lw 1.2GHz FM HT/TTP (Speetif) 473.00 349" 
IC-L2GAT lw 1.2GHz HT/batt/cgr/TTP 529.00 469" 



■ ■ i 1- ■ ■ 



Regular SALE 

525.00 479" 

625.00 569" 

Regular 

BC-35 7900 



Aircraft band hand held s 

A-2 5W PEP synth. aircraft HT.., 

A-20 Synth, aircraft HT w/VOR,, 

Accessories for all except micros 

BP-7 425mah/13.2V Nicad Pak - use 

BP^8 800mah/8.4V Niead Pak - use BC-35 ... 79,00 

BC-35 Drop in desk charger for all batteries 79.00 

BC-16U Wall charger for BP7/BP8. 21.25 

LC-11 Vinyl case for Dlx using BP3 .,,,. 20,50 

LC-14 Vinyl case for Dfx using BP-7/8 20.50 

LC-02AT Leather case for Dlx models w/8P 7/8 54.50 
Accessories for tC and iC-O series Regular 

BP-2 425mah/7.2V Nicad Pak - use BC35..., 49.00 

BP-3 Extra Std. 250 mah/8.4V Nicad Pak .... 39.50 

BP-4 Alkaline battery case. i 16.00 

BP-5 425mah/10.8V Ntcad Pak - use BC35 65.00 

CP'l Cig. lighter plug/cord for BP3 or Dlx.... 13.65 

CP-10 Battery separation cable w/clip 22.50 

DC-1 DC operation pah for standard models 24.50 

MB-16D Mobile mtg. bkt for all HTs 25.99 

LC-2AT Leather case for standard models 54 50 

HM-9 Speaker microphone , 4700 

HS-10 Boom microphone/headset. , ♦ 2450 

HS-10SA Vox unit for HS-10 & Deluxe only 24.50 

HS-10SB PTT unit for HS-10 24.50 

For other HT Accessories not listed please CALL 

Receivers Regular SALE 

R-71A 100kHz to 30MHz receiver,,.... $999.00 869" 
RC-11 Infrared remote controller.,,. 7099 

FL-32A 500 H? CW filter 69.00 

FL-63A 250 Hz CW filter (1st IF)..,,. 59.00 

FL-44A SSB filter (2nd IF) 178.00 159* 5 

EX-257 FM unit ♦,.♦,„ 49.00 

EX-310 Voice synthesizer............. 5900 

CR-64 High stability oscillator xtal 79.00 

SP-3 External speaker 65.00 

CK-70(EX-299) 12V DC option 12.99 

MB-I2 Mobile mount 25.99 

R-7000 25MHz-2GHz miffpttM)..... 1199.00 999" 
RC-12 Infrared remote controller .... 70.99 
EX-310 Voice synthesizer............. 59.00 

TV-R7000 ATVunit 139 00 129" 

AH-7000 Radiating antenna.. 99.00 

R-90O0 100KH^2GHz all-mode rcvr ... 5459.00 4699 



HOURS • Mon. thru Fn. 9-5:30; Sat 9-3 

WATS lines are for Quotes St Ordering only, 
use Regular line for other Into & Service dept 



Order Toll Free: 1-800-558-0411 



In Wisconsin (outside Milwaukee Metro Area) 

1-800-242-5195 





mmm 



i 



Inc. 



4828 W. Fond du Lac Avenue; Milwaukee, Wl 53216 

AES @ BRANCH STORES 



Phone (414) 442-4200 

Associate Store 



WICKLIFFE, Ohio 44092 
28940 Euclid Avenue 
Phone (216) 585-7388 

Ohio WATS 1-800-362-0290 

W 1-800-321-3594 



ORLANDO. Fla. 32803 

621 Commonwealth Ave, 

Phone (407) 894-3238 

Fla. WATS i -800-432-9424 

SSSiff 1-800 327-1917 



CLEARWATER, Fla. 34625 LAS VEGAS. Nev. 89106 CHICAGO, Illinois 60630 

1898 Drew Street 1072 N. Rancho Drive ERICKS0N COMMUNICATIONS 

Phone (813) 461-4267 Phone (702) 647-3114 5456 N. Milwaukee Avenue 

No In-State WATS No In-State WATS Phone (312) 631-5181 

No Nationwide WATS ^1-800-634-6227 ?ffi 1-800-621-5802 



ERICKSON COMMUNICATIONS 

5456 N. Milwaukee Avenue 

Phone (312) 631-5181 

?ffi 1-800-621-5802 



Number 13 on your Feedback card 



Packet Radio in Japan 

Bits of information on packet in the land of the Rising Sun 



by David Cowhig WA1LBP 



In the June 1989 issue of CQ Ham Radio 
(Japan)* Mr- Inoue JRIVMX points out 
that about 50 Japanese hams, mostly in the 
Tokyo area, now use the 9600 baud FAX 
modem chips made by Rockwell (the R96MD 
or R96FAX) or by Yamaha (the YM7910) to 
operate 9600 baud packet. These chips have 
become widely available with the prolifera- 
tion of G3 9600 baud FAX machines. JA8UY 
and JA6FTL successfully demonstrated G3 
ham radio facsimile at 9600 baud on 21 MHz 
SSB and 29 MHz FM. JIIFGX and J A 1 VAS 
have developed an Ethernet controller and 
microwave equipment for full duplex com- 
munications at 10 megabits per second at 10 
GHz, based on conventional wired LAN (lo- 
cal area network) technology. Important soft- 
ware upgrades have been made to several 
types of TCP/IP radio computer network sys- 
tems for rapid and efficient distribution of 
news along networks such as the JK1RJQ + 
JK1LGT Terakoya, and NOS TCP/IP 
systems. 

A Little Geography 

Japan, a country about the size of Califor- 
nia, has 1.6 million hams (ham operator li- 
censes last a lifetime in Japan) and about 
700,000 station licenses (station licenses are 
renewed every five years) concentrated most- 
ly along the seacoast on either side of the 
mountain ranges in the interior of the coun- 
try. As in California, the population density 
along the coast (about 40 million people live 
within 100 mi!es of Tokyo) and the advan- 
tages of high repeater sites in the mountains 
contribute to the popularity of the VHF and 
UHF bands. Few digipeaters and FM re- 
peaters use the very crowded 144-146 MHz 
band, but there are hundreds of repeaters and 
digipeaters on both the 430 MHz and 1200 
MHz bands. 

Can't Take Just One Byte 

For the English language, we need repre- 
sent only 26 letters of the alphabet in upper- 
and tower -case, the numbers zero through 
nine, and assorted symbols— all of which fits 
comfortably in 256 combinations. This lets us 
use only eight-bit bytes to represent a char- 
acter. 

Not so for the Japanese, who commonly 
use 2000 kanji characters and two sets of a 5 1 

38 73 Amateur Radio • October, 1989 



character phonetic syllabary. Japanese word 
processors and packet controllers (TNCs) use 
two bytes to represent each of 6000 charac- 
ters according to the JIS (Japan Industrial 
Standard) code. Shi ft- JIS uses two eight -bit 
digital blocks to create a 16-bit expression for 
a single kanji character, 

FAX in Japan 

Talking and sending written messages is 
fun T but how do you send a circuit diagram, a 
map, or a drawing to your fellow hams? 
Well, facsimile and packet image communi- 
cations have become popular in Japan. Many 
Japanese hams exchange drawings and maps 

"Shift JlS-uses 

two eight-bit digital 

signals to create a 

1 6-bit expression 

for a single kanji 

character/' 



by adapting the very popular G2 (minifax) 
telephone FAX machines for radio use. As 
the speed of these FAX machines increases, 
many Japanese hams buy inexpensive used 
FAX equipment. Some hams operate 4800 
baud facsimile machines which can send and 
receive a FAX graphic in less than one 
minute. Keizo Fukunishi JA8IJY demon- 
strated a simple interface circuit for 9600 
baud telephone FAX machines to put them on 
HF SSB and FM at 9600 baud, and a tuning 
circuit for receiving 9600 baud FAX signals. 
Transmission speed of these G3 FAX ma- 
chines can be stepped down as Low as 2400 
baud if necessary. 

Japanese hams are exchanging vivid, high 
resolution color graphics by packet radio 
using the North American Presentation 
Level Protocol Syntax (NAPLPS). Akihisa 
Kurashima JMLVSP wrote an implementa- 
tion of the Telidon NAPLPS videotex system 
which runs on IBM PCs with CGA or black 
and white monitors as well as on the NEC 
PC-9801 and several other Japanese comput- 
ers, NAPLPS uses the geometric method to 



create drawings using graphics commands. 

NAPLPS graphics data files are much 
smaller than those of drawings made using 
the photographic bit-by-bit method. 
NAPLPS can switch new character sets in 
and out of the 256 character set which can be 
specified using one byte. Thus, NAPLPS can 
use more than 256 characters in drawing pic- 
tures using supplementary character sets 
which may be N APLPS-standard, or user-de- 
fined. A packeteer can use the operation 
codes (op codes) of the Picture-Description 
set to perform operations such as drawing 
lines, arcs, rectangles, selecting which color 
to use, etc. The op codes and the character 
sets make it possible to send a high resolution 
graphics image using far less information 
than would be required to send the same 
image by a video system (slow-scan or fast- 
scan TV). 

Japan's Packet Wish List 

Today's packet dreams shape tomorrow's 
packet future. What are some Japanese pack- 
et dreams? Mr. Inoue JRIVMX: 

'Packet radio is the second great revolu- 
tion in amateur radio (the first opened up the 
shortwave bands). Packet radio brings hams 
together in a unique way . We need each other 
to maintain and operate the packet networks 
if packet is to work. Thus, we have a strong 
interest in improving the technical under- 
standing of our fellow hams. The arrival of 
9600 bps one-chip modems, and especially 
the successful experiments of Mr* Ueno 
JIIFGX with 10 megabit per second data 
transmissions at 10 GHz, open up new possi- 
bilities, Some of these are fast-scan TV trans- 
mission via packet radio and improved per- 
formance for today's TCP/IP news 
distribution networks and their interfaces 
with packet BBS. Packet databases and voice 
data transmission are becoming more practi- 
cal. Rapid advances in software , hardware 
and network organization are making this a 
very exciting time for ham radio, We are 
reaching towards our goal of free and reliable 
communications among all the hams of planet 
Earth." 



Dave Cowhig WA1LBP is 73 Magazine's 
Japanese translator, Contact him at 63 J 7 May 
Boulevard, Alexandria, VA 22310. 



& 




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9 Autry 

Irvine, CA 99718 

[714] 458-7277 




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•ICS— Intermittent Communication Service {50% Duty Cycle 5mm. on 5 min. off) 



Number 1 4 on your Feedback card 



Standardizing 
the Radio/TNC Interface 

Patch any rig to any TNC or data controller In just a few moments! 



by Brian Lloyd WB6RQN 



If you're like me, you want your packet 
station to perform welL To that end, 
you've carefully constructed a cable that con- 
nects your TNC to your radio, The cable has 
the appropriate TNC connector on one end 
and the appropriate radio connector on the 
other. YouVe also carefully adjusted your 
TNC to produce the proper signal level to 
modulate your rig to precisely 3 kHz devia- 
tion. The result is that everybody can copy 
your packets. 

Now you participate in a simulated emer- 
gency test, arriving, setting up. and operat- 
ing. Uh oh, the rig dies, and you have to make 
do with a different one. Thirty minutes, sev- 
eral clip leads, and much level -pot diddling 
later* you're back on the air— except no one is 
sending you any more traffic. If s all going to 
the voice operators, since their stuff was 
working and yours wasn't, 

Or maybe, like me, you have five TNCs 
and five radios. Life can get a little complicat- 
ed unless you dedicate each TNC to a particu- 
lar radio. What if you want to experiment, or 
just recover from a radio or TNC failure? 
You're out of luck. 

The Solution 

We! 1 , 1 got tired of both these situations and 
came up with a solution: a standardized ca- 
bling scheme that completely hides the differ- 
ences between my TNCs and radios, It makes 
the radios think all the TNCs have the same 
connector, pinout, and signal levels and, like- 
wise, makes the TNCs think all the radios 
have the same connector, pinout, and signal 
levels. 

If this situation actually existed, only one 
type of interconnect cable would be required 
between the TNCs and radios. In the real 
world, the situation can be mimicked by hav- 
ing two cables for each installation, one for 
each radio and one for each TNC. The cables 
then connect in the center using a standard 
connector. 

The Standard Interface 

To do this, I first had to define my "stan- 
dard' interface. I chose a DB-9 connector, 

40 73 Amateur Radio • October, 1989 



OlOTttEH DETECT 

Kill to ground 

TO INDICATE - iR4£lt 



TEtWiAL 



\ 






AUDIO FROM RECEIVE* 
MXJiwiVRMS 

*FS* TO TftANSwTTEfi. 

\ 




TRANSMITTER *£*■ IRTTI 
PULL TO CRQUfc© T& *C * 
TRfiNSM4TTE«. 



Figure J. The author chose the DB-9 con- 
necter as the "standard" interface connec- 
tor, because of its ubiquity and good shield- 
ing properties. 






4 H:H 



N/C J 



STANDARD 
4 CWNECTQR 



SHIELD 



5 

G-9 



ID0 
p EMALF_ 



7-9 N/C 



• VimRGNICS 



I 



Z N/C 

i 



TNC 

06-9 



% — 

6-9 



Kft z 



N/C 1 



91 
FEMZLE 



V'SKE 



•:-: 



DRSi 



Z 1 
















TNC 
[01 N- 5) 


■ 




































"i — 


















5m£LQ 






















TNC-Z 







3 STAND A q[) 
CONNECTOR 
(08-91 

* FCMALI 

E-9 



Figure! Schematics for patching the "stan- 
dard" interface connector to three popular 
TNCs. 



since they're readily available (Radio Shack 
carries them) and they're available with 
shielded hoods, so it's easy to construct a 
fully shielded cable assembly. Figure I 
shows the standard interface connector I de- 
signed and the signals passing through it. 

The TNC Cable 

With the interface already designed, your 
next step is to construct the TNC cable, since 
it's the most straightforward. This cable will 
have the appropriate TNC connector on one 
end— DIN-5 for TNC-2: DB-9 for TNC-1, 
DRSI, or Kantronics; and so forth— and a 
DB-9 " standard M connector on the other. 
Figure 2 shows the schematics for several 
popular TNCs* 

Because TNCs are both sensitive to RF and 
wonderful producers of EMI. be sure to use a 
well shielded cable and use ferrite beads to 
head off the flow of RF, I put a single large 
bead over the whole cable to reduce or elimi- 
nate RF from the outside of the shield. 

Once the TNC cable is finished, you must 
adjust the TNC to produce the "standard" 
transmit signal level. I chose 300 mVRMS 
because it should be more than sufficient to 
drive any radio. Most TNCs include a trim- 
pot to set the transmit audio level, Simply 
adjust the pot to produce a 300 mVRMS sig- 
nal into a 500Q load. 

If you have a Kantronics TNC ♦ you'll have 
to modify it slightly , using a "standard" mod 
described in the Kantronics documentation. 
Kantronics uses a jumper to select one of 
three transmit signal levels. Choose a resistor 
value for one of the jumper positions that will 
set the output level to 300 mVRMS. 

The Radio Cable 

Now to construct the cable that hides the 
differences between radios. This cable is a bit 
more complicated, since it must map the stan- 
dard pinout to the pinout of the transceiver's 
connector, attenuate the standard 300 mV 
signal level to the level expected by the radio, 
and deal properly with the different PIT 
schemes. 

The biggest problem is attenuating the 



OIN 






' 


" 














ft * r S*nrLO 


- <mniiiin 


StANDAAO 
CONNECTOR 
IDB-tl 
MALE , 






4 




' RECEIVE AUDIO 


tOPTiONALJ 


T 


EPICAL fllflDtO 


V ■ ' ' 



Figure J. Radio interface cable diagram for 
many types of transceivers. 

signal to the proper level so thai, in the case of 
u VHF or UHF NBFM radio, the high tone 
generates 2.5 to 3.0 kHz of deviation. I usual- 
ly start out using a trimpot to determine the 
proper amount of attenuation* and then re- 
place the trimpot with two resistors. As long 
as you don't change the deviation control in 
the radio, the cable will always ensure proper 
modulation. 



"Because TNCs are both 

sensitive to RFand 
wonderful producers of 

EMl f he sure to use a 
weli shielded cable and 

use ferrite beads to 
head off the flow of RF. " 



Most radios use the same technique for 
keying the rig: They pull the ptt line to 
ground. This means that all you need to do is 
route the ptt line from the TNC to the radio's 
ptt line. 

Some radios, notably handhelds. have a 
different ptt control scheme. ICOM uses 
continuity to ground from the center pin on 
the mike jack to key the transmitter. A Ken* 
wood is keyed when the mike ring connector 
is connected to ground {the audio-out or ex- 
ternal*speaker ground) . 

Figure 3 shows interface cable schematics 



PIN 

I - 



€-* 



lit; V 






-■ i.: 



CGMHECTon 

t**J.E 



10 K 



-1 



— ^ M1K.E TIP 



-> MIKE RING 

£UBMlttlATU«£ 
PLUG 



5 



4 5J»«R RING 

■* £PKf» TIP 

MINIATURE PLUG 



3 N/C 

4 HfC 



Figure 4. , . , and for an ICOM HT. . . 



STANDARD 
CONNECTOR 
JDH-9J *** 

UMLE 






— i n" 

IK 

. i;ai 




Mime TP 
*MHATUft£ PLUGJ 



3 



-> SPUR fllNG 



— ^ SPKR tip 

SUBMINIAT1.FRE 
PLUG 



A N/C 



signal level. Adjust the pot for 3 kHz devia- 
tion of the transmitter when the standard level 
of 300 mV is applied to the cable. After 
adjustment you can measure the trimpot and 

replace it with two fixed resistors to make 
your cable more compact. 

When you get your setup working, swap 
TNCs and radios with friends to make sure 
everything is truly universal. From then on 
you can rest assured that making changes in 
your packet station will be a ' 'plug and play 7 
operation! 



Figure 5. . . .and for the Kenwood TR-25QQ 
HT, 

for a typical radio, Figure 4 shows the same 
for an ICOM HT, and Figure 5 shows the 
same for a Kenwood TR-25GQ HT. Notice 
that each cable includes a trimpot to set the 



Brian Lioyd WB6RQN has pursued amateur 
radio enthusiastically since age eight. He re- 
cently co-founded Sirius Systems, a network- 
ing business in Petersburg. Virginia. You 
may reach Brian at: 5712 Still well Rd* t 
Rockviile MD 2085 L 




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73 Amateur Radio • October, 1989 41 



73 Review 



by Philip R. Karn, Jr. KA9Q 



Number 1 5 on your Feedbacl card 

GRAPES. Inc. 

PO Box 871 

Aipharetta GA 30239-0871 

Price Class: $250, in kit form 



GRAPES 56 Kb Modem 

We've come a long way from 1200 baud packet. 



How would you like to be able to send the 
equivalent of a standard 5.25" IBM PC 
floppy disk (360 Kbytes) by packet radio in less 
than Iwo minutes? How about transmitting 
telephone-quality digital voice over the air? 
Sound too good or expensive to be true? Not 
at alll it's being done right now, with equip- 
ment and software available to any interested 
amateur. 

The key is the 56 Kb/s modem designed by 
Dale Heatherington WA4DSY and distributed 
by the Georgia Radio Amateur Packet Enthu- 
siasts Society (GRAPES). Since its unveiling 



MSK - Minimum Shift Keying 



l 2 data rate: "devtotkm" —14 date rate 
Ai 56 KSpv ilufl - 28KHZ. dntetfon = - U KHz 



O 

4 




rotates ezacily -<K> during 



^ I 



Figure f. MSK, a form of Frequency Shift Key- 
ing (FSK), uses the smallest possible mark/ 
space frequency shift for the data rate in use. 
This keeps the signal bandwidth to a minimum. 



MSK * Minimum Shift Keying 


(WA^OSf) 


Modified MSK 


Q 


i 


Phas* vefcKJtte* 
^"S. crurvgc " gracr fully": 
%/\ arnpftkjite nan-comtanfl 




~st *" 

f f bflftef Sfwcfral 
Xy ciiaracteftst ic* 1 fttvt 



Figure 2. The SB Kb modem uses a modified 
form of MSK. 

at Dayton in 1987, this modem has pro- 
gressed through the experimental and beta 
test stages and is now in routine production 
and use. 

Keying Scheme 

The WA4DSY modem uses a modified form 
of Minimum Shift Keying (MSK) [see Figures 1 
and 2) r MSK is just a special form of Frequen- 
cy Shift Keying (FSK). well known to every HF 
RTTYer. As the name implies, though, MSK 
uses the smallest possible mark/space fre- 

42 7$ Amateur Radio * October, 1989 



quency shift for the data rate in use, keepmg 
the signal bandwidth to a minimum. 

In RTTY terms, the carrier "shift" in Hz is 
equal to one-half of the data rate in bits per 
second; at 56,000 bits/sec T the mark/space 
shift is 28 kHz. In FM terms, the "deviation" of 
the signal is plus and minus one-quarter of the 
data rate, or ± 14 kHz at 56Kb/s. ff you select a 
different speed in the modem, the shift 
changes automatically; the transmitted signal 
is generated digitally in a state machine, so 
you can't get it wrong! 

The WA4DSY Modem Kit 

The kit includes three PC boards: transmit 
encoder, receive decoder, and RF board, 
plus all necessary board parts except the 
channel crystals. Unlike virtually all other 
amateur packet radio modems, the WA4DSY 
modem is not an add*on to a standard voice 



Rf Board <RX Half) 



if; 

IN 



> 



10J MHl 

Cartmte 

FUum 




dh 



MC335G 



Filter 



flXLO 



Figure 3. The receive portion of the WA40SY modem 
design. 



transceiver, Instead, it operates with a VHF or 
UHF transverter (transmit/receive converter) 
such as those made by Microwave Modules or 
SSB Electronics. You must buy the transvert- 
er separately. 

Transverters have the needed bandwidth to 
pass the high speed modem signal (75 kHz). 
Also, they are typically cheaper than full-voice 
transceivers because they lack an audio sec* 
tion, synthesizer, and the other extras that 
aren't necessary for dedicated packet opera- 
tion. The RF section of the WA4DSY modem 
operates near 28 MHz, so you can use it on 
any band where you can use a transverter 
designed for a 1 meter transceiver. (Because 
of FCC bandwidth limits, however, you may 
only use this modem at fult speed on frequen- 
cies above 220 MHz in the US, See section 
97.69 of the regs.) 

The RF modulator produces approximately 
1 mW (0 dBm). enough to drive the Microwave 
Modules transverter. configured for low drive 
level to fult power. The RF demodulator is 



sensitive enough to work well when fed direct- 
ly from a typical receive converter- The 
transverter must be modified to decrease its 
transmit/receive switching time, but this is a 
simple operation involving the removal of a 
single capacitor. 

The WA4DSY modem design is highly mod- 
ular. You can saw the RF board's receive and 
transmit into halves and build completely in- 
dependent receivers and transmitters if you 
wish (e.g., for dedicated, fulf duplex links). 
See Figures 3 and 4. 

The digital side of the modem provides six 
interface signals, three each for the transmit* 
ter and the receiver. All signals are TTL levels; 
if the host computer uses RS-232 signals you 
must either modify it to produce TTL or insert 
RS-232/TTL levet converters, 

As standard with commercial high speed 
synchronous modems, the WA4DSY modem 
provides both transmit and re- 
ceive bit clocks, This eliminates 
the need for a baud rate generator 
in the host computer interface. It 
also means you can use older and 
less expensive HDLC chips like 
the Zilog SIO without having to 
provide a "state machine" circuit 
like that in the TAPR TNC-2 for 
recovering clock from the receive 
data stream. 

In addition to the data and 
clock input/output signals, the 
WA4DSY demodulator also 
accepts a Request-to-Send (RTS) 
signal for keying the transmitter, 
and it provides a Data Carrier Detect (DCD) 
signal. 



Baaatund 
DATA 
OUT 




Figure 4. The transmit half of the WA4DSY 
modem. Since the design is modular, you 
can saw the RF board in half to set up a com- 
pletely independent receiver and transmitter 
section. 



uniden 



® 



$1$19M$1$19 



$12, 

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Uniden Corporation of America has pur- 
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celebrate this purchase, we're having our 
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ends September 30> 1989. 

• * * MONEY SA WING COUPON* * * 

Get special savings on the scanners 
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Credit ce rds. personal checks and quan- 
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mailed directly to Communications Elec- 
tronics inc., P.O. Box f 045- Dept UNI6 r 
Ann Arbor, Michigan 48 1 06- 104 5 U Si A 
Coupon expires September 30, 1989, 
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may be photocopied Add SHOO tor 
Shipping in the continental USA 

Regency TS2-T $259.95 

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Regency R2060-T1 $114,95 

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Regency RH256B-T $294.95 

Bearcal 20OXLT-T $249.95 

Bea rest 1 00XLT-T $1 84.95 

Bearcat 800XLT-T $249.95 

Uniden HR2510-T $229,95 

Uniden PRD500OT1 $32.95 

T+ * + VALUABLE COUPON *** + 

Bearcat? 760XLT-T 

Ust price S499.95/CE price $244,95/SPECIAL 
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Frequency range; 29-54 r 118-174, 406-5 12,806-956 MHz. 
Excludes &23.9S 75-849 0125 and 868.08 75-894 1 25 MHz, 

The Bearcat 76QXLT has 100 programmable Chan- 
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10 Channel e 25 Wart Transceiver • Priority 

The Regency RH256B is asixteen-channel VHF land 
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synthesized, no expensive crystals are needed to 
store up to 1 6 frequencies without battery backup. 
All radios come with CTCSS tone and scanning 
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PR031 DE-T Uwden 40 Ch. Pon able/ Mobile CB 583 95 
PRG33QE-T Untden 40 Ch Remote mount CB . Si 04 95 

PR05OOO-T Untden 40 Channel C8 Mobile $38 95 

KARATE*T Untden 40 channel rescue radio . „ „ . . $5395 

GRANTT Untden 40 channel SSB CB mobile S 166.95 

M A D I SO N - T Untden 40 ch a n ne I SSB CS base S 244. 95 
PCt 22-T Untden 40 channel SSB CB mobile. . . S1 1995 

PR0510XL-T Untden 40 channel CB Mo&dfr. S38 95 

PRO520XL-T Uniden 40 channel CO Motnifl S56 95 

PHOS30XL-T Uniden 40 channel CB Mobile. S79 95 

PRO54.0E-T Urttden 40 channel CB Mobue. .*,.. $97.95 
PR0640E-T Untden 40 channel SSBCB Mobile 5137.95 

PRO? 1 0E-T Uniden 40 channel CB Base ..511 9.95 

PRQB10E-T Uniden 40 channel SSB CB Base SI 74.95 

it it * Uniden Radar Detectors* • • 

Buy the finest Unrden radar detectors from CEI today. 

TALKER-T Uniden talking radar detector $104.95 

R07-T Uniden visor mount radar detector $99.95 

HD9-T Umden "PsssoorT size rsdar detector — 51 14.95 

RD9XL-T Uniden "mkrro M sue radar detector 5144.95 

RD25-T Untden vi&or mount radar detector $54.95 

RD50O-T Uniden ^iaor mount radar detector $74,95 

Bearcat® 200XLT-T 

List price S509.95/CE price S254.95/SPECJAL 
1 2- Band, 200 Channel • 000 MHx* Handheld 
Search * Limit * Moid • Priority • Lockout 
Frequency range: 29-54 118- 174, 406-51 2 r QQ&-956 MHz. 
Excludes 823.98 75-049 01 25 and 868 9&75&94Q125 MHi 

The Bearcat 200 XLT sets a new standard for hand* 
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This full featured unit has 200 programmable 
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AC adapter and earphone Order your scanner now 



Bearcat® 800XLT-T 

List price 5549.95/CE price $259. 95/SPECIAL 
12- Band, 40 Channel • No- crystal scanner 
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The Uniden 800 XLT receives 40 channels in two banks 
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Bearcat®! 45 X L-T 

List price S1S9.95/CE price $94, 95/SPECIAL 
10- Band, 1 tf Channel • No-crystal scanner 
Priority control • Weather search # AC/ DC 

Bands: 29-54, 1 36- 1 74, 406*5 1 2 MHz. 
The fiearcat 145XL Is a 16 channel, programmable 
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mobile mounting bracket and mobile power cord. 

President® HR2510-T 

Us! price S499.95/CE price $239 + 95/SPECIAL 
f Mater Mobile Transceiver • Digital VFQ 
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PUT a Preprogrammed 10 KHz, Channels 
Frequency Coverage 28 0000 MHz lo 29.6999 MHz. 

The President HR251 Mobile 1 Meter Transceiver 
made by Uniden, has everything you need for 
amateur radio communications. Up to 25 Watt PEP 
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PA mode. Digital VFO. BuiIMn S/RF/MOD/SWR 
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much more? The HR2510 lets you operate AM. FM r 
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may choose either pre-programmed 1 KHz, chan- 
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List price S599.95/CE price $299. 95/SPECIAL 
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De fi vgry to r th is new p rodu c t !& Sen eduled tor June, 1989. 
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* + + Extended Service Contract if it it 
If you purchase a scanner, CB. radar detector or cordless 
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contract from WarrantecK This service ejciension plan begins 
after the manufacturer's warranty expires Warrantee n will 
perform ail necessary Jabor and wilt not charge tor return 
Sh ippi ng E 1 f end ed service contracts are not refundable and 
apply only to theonginat purchaser A two year extended Con* 
trad on a mobile or base scanner is S 29 99 and three years is 
S3g 99 For handheld scanners, 2 years <s S59 99 and 3 
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BC55KLTT Searcaf 10 channel scanner — St 14 95 
BC70XLT T Bearcat 20 channel scanner $ 1 59 95 

BC 1 7 5XLT-T Bea/csl 1 6 channel scanner $ 1 56 95 

H206O-T Regency 60 channel scanner , . . $1 49.95 

TS2-T Regency 75 channel scanner $269 95 

UCt02«T Regency VHF 2 ch. 1 Watt transceiver $1 14 95 

BPS5-T Regency 1 6 amp reg. power supply $1 79.95 

BP205-TN1 Cad batt.pacK tor BC200/BC10OXLT $4995 

B8-T 1 .2 V AA Ni-Cad batteries (set of eight) $1 7.95 

FBE-T Frequency Directory for Eastern U.S^A $1 4.95 

FBW-T Frequency Directory for Western US, A $14,95 

RFD1 -T Great Lakes Frequency Directory $14.95 

RFD2-T New England Frequency Directory $14,95 

RFD3-T Mid Atlantic Frequency Directory $14.95 

RFD4T Southeast Frequency Directory.. .,..$14.95 

RFD5-T NW& Northern Plains Frequency Dlr . . $14 95 

ASD-T Airplane Scanner Directory * , t $14 95 

SflF-T Survival Radio Frequency Directory $14.95 

TSO-T 'Top Secret - Registry of U S Govt. Freq, $14 95 

TTC*T Tune in on telephone calls .**,.*- ,$14.95 

CBH-T Big CB HandbooVAM/FM/Freeband $14 95 

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EEC-T Embassy A Espionage Communications $14 95 
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A0O-T Magnet mount mobile scanner antenna $35 95 
A70-T Base station scanner antenna . $35 95 

A1 SOO-T 25 MHz.- i.3GHi Otscone antenna $ 1 09 95 
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USAK-T V hole mount VHF ant mi 1 7 cable $35 95 

Add $4 00 shipping for all accessones ordered at the same time. 
Add $1 1 00 shipping per radio and $4 00 per antenna. 

BUY WITH CONFIDENCE 

To get the fastest delivery from CM! of any scanner, 
send or phone your order directly to our Scanner 
Distribution Center* Michigan residents please add 4% 
sales ta* or supply your tax f.D. number. Written pur- 
chase orders are accepted from approved government 
agencies and most well rated firms at a 1 0% surcharge 
tor net 10 billing. All sales are subject to availability, 
acceptance and verification. All sales on accessories 
ar e final. Prices, terms and specifications are subject to 
change without notice. All prices are in US. dollars. Out 
of stoc kitemgwilibep! seed on backo rder a utom at tea 1 1 y 
unless CEI is Instructed differently A $5 00 additional 
handling fee will be charged tor all orders with a 
merchandise total under$50.00. Shipments are F.O.B. 
CEI warehouse In Ann Arbor, Michigan, No COD's, 
Most items listed have a manufacturer's warranty. Free 
copies of warranlies on these products are available 
by writing lo CEI Non-certified checks require bank 
clearance. Not responsible for typographical errors 

Mail orders to: Communications Electron- 
icsr Box 1045. Ann Arbor, Michigan 48106 
U.S A. Add $11. 00 per scanner for U, P. S. ground 
sh ipping and handling in the continental U.S.A. 
For Canada, Puerto Rico t Hawaii, Alaska, or 
APO/FPO delivery, shipping charges are three 
times continental U.S, rates. If you have a 
Discover, Visa, Am e near* Express or Master 
Card, you may call and place a credit card order. 
5% surcharge for billing to American Express. 
Order toK-free in the U.S. Dial 800- USA- SCAN, 
In Canada dial 800-221-3475. FAX anytime, 
dial 313*971-6000. If you are outside the U.S, 
or in Michigan dia!31 3-973-8888. Order today. 

Scanner Distribution Center" and CEI logos are trade* 
marks of Communications Electronics inc. 
Sale dates 3/S/89 - 9/30/S9 *o »0308B^T 

Copyright - 1989 Communications Elfrctranlcs Inc. 

For credit card orders call 

1-800 -USA- SCAN 

fftl 



COMMUNICATIONS 
ELECTRONICS INC. 
Consumer Products Division 

PO. Bo* 1045 n Ann Arbor. Michigan 48 1061045 US A 
For ord*rs call 31 3-973-3888 Of FAX 31 3 97 1 6OO0 

CIRCLE 12 1 ON READER SERVICE CARD 




Construction and Alignment 

The kit provided by GRAPES in- 
cludes complete documentation 
and all parts required to populate 
the three main boards except for the 
channel crystals (two are required: 
one tor the transmitter and one tor 
the receiver). ( found the kit conve- 
nient and easy to assemble, partic- 
ularly after having built two of the 
early "bare beta board" versions of 
the modem when I had to scrounge 
tor my own parts! Nothing was miss- 
ing, and I had the boards together in 
a weekend. The location of each 
part was silk-screened into the RF 
and receive decoder cards. 

Although (here was no silk screen 
on the transmit encoder card (see 
Figure 5). I had no problem putting 
everything in its place using the 
parts placement diagrams. 

As mentioned earlier, the modem 
can operate at speeds other than 56 
Kb/s. Dale was careful to place all of 
the speed-determining compo- 
nents on plug-in DIP headers on the 
transmit encoder and receive de- 
coder cards, so you don't have to 
unsolder anything to change 
speeos. 

The bandwidth of the receive IF 
fitter on the RF board is fixed, how* 
ever, so you'd have to do some sol- 
dering and recalibrating there if 
changing speeds. I don't know of too many 
people, however, who have operated these 
boards at speeds below 56 Kb/s! 

Modem Setup 

Alignment of the modem requires an oscillo- 
scope, preferably a dual-trace model, The in- 
structions are fairly clear, and tweaking the 
transmit encoder card took only a few min- 
utes. The RF card lakes a little more work, I 
was fortunate to have the use of an IFR 12003 
Service Monitor to make the alignment of Ihe 
IF bandpass filter coils in the receiver a two- 
minute job, but it f s not that much harder with 
just the scope. I did notice something on the 
IFR's spectrum analyzer while setting the 
power gain adjustment in the transverter: 

If you crank the wick all the way up. the 
signal sidebands come up noticeably. It's best 
to sacrifice a few watts to let the 
transverter have some headroom. 
The modem signal is a specially 
modified form of MSK with some 
deliberate amplitude modulation to 
reduce the extra sidebands, so you 
want to operate the transverter in its 
linear region. If you do this, the 
spectrum is very clean. 

Once the RF board was aligned, 
the receive decoder card adjust- 
ments were very straightforward 
(see Figure 6). I did have one prob- 
lem with false triggering in the 
NE555 IC in the clock recovery cir- 
cuit (see Figure 7); I fixed this by 
soldering a miniature 0.1 pF capaci- 



Transmit Encoder 




Gam& Balance 



Figure 5. With the parts placement diagrams, it's easy to assemble 
the transmit encoder. 



Bulbil nl 

In 



Receive Decoder 



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D escia mblt 



Data Out 



DC A(Sj 



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Si iter 



dt 



£ + H 



t 




N 



m 

_MfVL_ 



VCO 



Cluck 
Out 




t 



Loop Filler 



Detect 



_/WV^ 
Squetch 



OCD 



Figure 6. The receive decoder card adjustments are straightforward. 



Haw 

Baseband 

Data 

from 

Dcmod 

C'Eye") 

nmvBfH 
Clock 


Receiver Clock Recovery 


O 


CX 


Sample 

l 
l 

i 
i 

i 


\ 

1 
I 

I 
I 

i 























Figure 7 + In the clock recovery circuit, the au- 
thor soldered a miniature 0.1 pF capacitor 
across the supply and ground pins on the un- 
derside of the socket. 



fa 



swmvu* 



CLOCK 



7 X DATA 



III'-, 






WTS 



r 



I 




Figure 3. The 56 Kb modem system. The GRAPES kit includes three 
PC boards: transmit encoder, receive decoder, and RF board r plus 
all necessary board parts except the channel crystals. 



tor across the supply and ground 
pins on the underside of the socket. 

Assembly 

The GRAPES kit contains no chas- 
sis; you have to find one and drill 
your own holes. I've been using the 
10" x 12" x 2" Hammond aluminum 
chassis, as I can arrange the boards 
for easy access to the adjustment 
screws and test points. You can cer- 
tainly use more compact (or more 
attractive!) cabinets, if you prefer. 
The modem requires a source of 
±5V DC t plus whatever the 
transverter requires (typically + 1 2V 
DC). I used some small surplus 
Japanese-made switching power 
supplies sold by Radio Shack for 
the bargain price of S5. This was 
five years ago, and unfortunately 
they are no longer available. Suit- 
able AC power supplies are certain- 
ly available, but if you prefer 1 2V DC 
operation, you can use a linear reg- 
ulator to generate +5V, The 
modem's -5V requirements are 
minimal, so a simple charge pump 
circuit will do just fine. 

Up and Running 

This modem challenges you to 
figure out how to move data to and 
from your computer fast enough! 
The early experiments in Atlanta 
with this modem used modified 
TNC-2s; the mods consisted of beefing up the 
digital components (CPU, SIO. memory), 
eliminating the internal Bell 202 modem, and 
installing a modified copy of the KISS TNC 
EPROMs. The TNC was then connected to an 
IBM PC host computer running my TCP/IP 
package. 

This worked, but the serial link between the 
TNC and host computer was still not fast 
enough. The cost was unappealing. But if 
you're interested, the details are included with 
the modem kit documentation. 

Problems and Adaptations 

When 1 obtained my modems a year ago at 
Dayton, I also picked up a PCPA (PC Packet 
Adaptor) card from DRSI (Digital Radio Sys- 
tems, Inc). The PCPA is a plug-in adaptor card 
for the IBM PC bus that contains a Zilog 8530 
HDLC chip, a Bell 202 modem, and 
associated '"glue" parts. Bypass- 
ing the modem and RS-232 drivers 
(a procedure described \n the DRSI 
manual), I was able to connect the 
PCPA's 8530 Chip directly to the 
modem with a ribbon cable. 

Then 1 wrote a special software 
"driver" module for my TCP/IP 
package that accesses the PCPA's 
6530 chip directly, passing data at 
the full 56 Kb/s rate of the modem. It 
works, but at a cost: because of the 
high data rate, the computer has its 
hands completely full whenever the 
modem is active, transmitting or re- 
ceiving. Everything else (keyboard 



44 73 Amateur Radto • October, 1989 



echoing, the tJme-of-day dock, etc) momen- 
tarily grinds to a halt! 

This is not ideal, so work is underway to 
develop a "smart" card with its own CPU to 
handle the low-level tasks of talking to a high 
i,peed modem, freeing the main CPU for other 
-htngs. Mike Chepponis K3MC has built a pro- 
totype, and my next step is to program it. But 
until then, we can use the DRSI PCPA and its 
functional equivalent, the PacComm PC-100. 
(You can also use a board called the "Eagle 
card, "once sold surplus by the now*defunct 
Eagle Computer company, if you can get one.) 

Packet in the Fast Lane 

It should not surprise you that it's VERY 
easy to get spoiled by 56 Kb packet! Once 
you've had a taste, there's no going back. 
Even my 9600 b/s telephone modem seems 
slow in comparison, and one wonders how 
anyone could possibly tolerate 1200 b/s! 

But to be fair, 56 Kb is not without its 
problems. 

The first problem is probably fairly obvious; 
There aren't that many people around to talk 
to yet! The situation here in Northern New 
Jersey on 220.55 MHz (the local 56 Kb/s chan- 
nel) is much like 145.01 MHz was back in 
1983. Our 56 Kb network presently consists of 
KA9Q, WB0MPG. KA9Q-2 {a digipeater/IP 
switch) and N2AER; we expect N4HY and 
N7AKR on the air soon. High speed packet is 
now at roughly the same stage that 1 200 baud 
packet was in the early 1980s, and with luck 
it'll become as popular. 

The keyup delay required by the WA4DSY 
modem isn't as small as i would like. We're 
currently running with transmit delays of 
about 15 milliseconds. This may seem short 
until you realize that in 15 ms at 56 Kb/s, you 
can send 1 00 characters! Many packets aren't 
this big, even when you include full TCP, IP, 
and AX,25 protocol headers. 

The data carrier detect (squelch) circuit in 
the WA4DSY demodulator could probably be 
improved Although it works reasonably well 
(better than the DCO circuits in most slow 
speed packet modems) it can be tricky to ad- 
just and the threshofd sometimes varies due 
to front end desensing. (Perhaps this is an 
unfair criticism; I live about 500 feet away from 
a 220 MHz FM repeater ) 

High speed operation requires wide band- 
widths, As mentioned, the WA4DSY modem 
occupies about 75 kHz when running at 56 
Kb/s; it is generally operated in a 100 kHz 
channel. This is about five times the band- 
width of an FM voice channel (20 kHz), so ftve 
times as much noise enters the modem re- 
ceiver's passband as compared to a regular 
FM voice receiver. 

Therefore, the 10 watts of 56 Kb/s RF com- 
ing out of my transverter is like 2 watts of FM 
voice RF— not much, Mullipath is also a prob- 
lem (100 kHz is half as wide as a commercial 
FM broadcast channel.) Seams and good 
sites help, but sometimes there is no substi- 
tute for a power amp. 

An aside: The spectral efficiency of a 
modem isn't measured by its bandwidth 
alone, but by the ratio of the bandwidth to the 
data rate. Although the WA4DSY modem re* 



quires five times the bandwidth of a standard 
1200 baud packet signal, its data rate is 46,7 
times faster This makes it about 9.3 times 
more spectrally efficient than the latter. 

This wide bandwidth also limits us to 220 
MHz and up, both a blessing and a curse. It's a 
blessing because 2 meters really isn't the 
proper place for serious packet operation be- 
cause it's too crowded, at least in densely 
populated areas like New York, It's a curse 
because propagation isn't as good on the 
higher bands, and transverters are more ex- 
pensive. Nonetheless, we'd better get active 
there in any event, since spectrum theft by 
other services can strike at any time. If Docket 
87-14 is upheld and we are unable to find 100 
kHz of space above 222 MHz, my friends and I 
are going to have to junk some perfectly good 
transverters. 



The availability of high speed modems, in- 
terface cards and host computers does not 
guarantee maximum throughput; careful net- 
work engineering is still necessary, But the 
WA4DSY modem is a major contribution to 
amateur packet radio, and it has the potential 
to be as revolutionary as the original Vancou- 
ver and TAPR TNCs. 



Phil Kara KA9Q works for Belt Communica- 
tions Research (Be ff core) designing and 
maintaining internal networks. He is one of the 
founding fathers of amateur packet radio, as 
he co-authored the AX.2S protocol specifica- 
tion. Phit is a member of the Board of Directors 
of the Tucson Amateur Packet Radio (TAPR) 
group, and is very active in AMSAT. You may 
contact Phil at 25-B Hi f forest Road. Warren NJ 
07060. 



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The 96 is tough. A three- terminal 
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that its proven performance in the 
field allows us to offer two year 
warranty coverage which includes 
damage caused by lightning! 

You'll hear thunderous applause 
when you Install a *96 controller on 
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your repeater from anywhere with- 
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Your users will be thunderstruck by 
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CIRCLE 1 ON READER SERVICE CARD 



Continued from page 32 





Parts List 




Part 


Use 


Radio Shack # 


Metal Bo* 


Cabinet 


270-272 


4-Pin Mike Jack 


Headset Jack 


274-002 


4*Pin Mike Plug 


Headset Plug 


274-001 


DB-9 Female (2) 


VHF Box Connect 
HF Cable Connect 


276-1538 


DB-9 Male {2} 


VHF Cable Connect 


276-1537 




HF Box Connect 




Phono Jacks (4) 


VHF & HF 


274-346 




AFSK & PTT 




1/8" Mini Jacks (4) 


VHF & HF 
Audio In/Out 


274-251 


1/8* Mini Jack (1) 


Remote PTT 


274-251 


3PDT Mini Toggle (2) 


NORM/REV & 
KAM/HS 


275-661 


DPDT Mini Toggle (1) 


NORM/WEFAX 


275-663 


SPOT Mini Toggle (1) 


REC/XMIT 


275-662 


Mini Shielded Cable 


Wiring 


278-752 


Misc.: Solder lugs, audio cables, dry transfer lettering, clear acrylic 


spray paint . 







slowly. If part of the letter remains on the 
backing . lower it back to the surface carefully 
and rub again. You quickly get the hang of it, 
and they make a project look very professional > 
With the lettering done, I sprayed both 
surfaces with several coats of clear acrylic. 
Always test the spray first. All the acrylic 
sprays I have used so far haven't caused prob- 
lems, but there are some sprays that make the 
lettering dissolve and run. Spray several light 
coats with plenty of drying time in between. 
You don't want any runs on the front panel! 

Installing the Ports and Switches 

I let the box sit for a night or two, then 
mounted the switches and connectors. Once 
they were in place and carefully tightened 
down it was time to heat up the old soldering 
iron. 

I used miniature coax for the wiring for 
several reasons, most of them having to do 
with RF1 (We already get enough noise in our 
transmit and receive signals.) Ground the 



shield of at least one end 
of each wired connection 
in the box. Remember to 
first make a good me- 
chanical connection with 
the wire to the solder lug, 
rhen make a good solder 
connection. Keep all leads 
as short as possible, mak- 
ine i hem nearly taut* 



Adding Accessories 

The Telex headset had 
a commercial plug on it. 
I could find no markings 
as to which pin was for 
the earphones and which 
was for the mike, Hang- 
ing the earphones tin my 
head and using the ohm 
position of my multime- 
ter, I checked between the center wire and the 
shield of each wire. I heard the crackle in the 
phones. That identified the phone wire, The 
other was obviously the mike, I wired a com- 
mon, four-prong mike plus to the cable to 
match the four-prong jack on the switch box, 
i took time out from the box to install the 
DB-9 plugs on the RAM cables. I used the 
diagrams in the RAM instruction manual to 
identify the wires. Shielded audio cables 
from my junk box made the PTT and AFSK 
cables for both HF and VHF. The FT-767GX 
uses phone connectors for Patch input and 
PTT input. For the two meter, I stripped one 
end of the cables and soldered them to a mike 
connector. 

Checkout 

I went back over each wire, one at a time, 
tracing it in comparison to the schematic, I 
didn't want PTT voltage going into a receive 
audio circuit or some other IC eater, chewing 
up my rigs! Satisfied that it was close to 



(JkFSCl - 
(«CD1 - 



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• I t AUDIO i/Ol » 
5 • (AUDIO i/03 • 

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PS 

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tAFSKt *- 
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<FS*1 * 



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* SMALLER SEPARATE WWE On KAM VHF/NF CONNECTORS 



Figure L KAM Box schematic. An easy one -afternoon project* 
46 73 Amateur Radio • October. 1989 



correct, I plugged up the cables and gently 
powered up the devices. 

The buzz saw of packet ripped the two 
meter speaker and text unraveled across the 
computer screen. One quick fix, and I ran it 
through the rest of the modes and found one 
problem. A quick look and then moving one 
wire to the other side of a switch fixed that 
one. Even with my second and third recheck, 
I had missed thai one, 

It all worked pretty much as I had expected. 
The headset worked nicely. With a foot 
switch plugged into the remote PTT jack 
I could work DX and log with two free 
hands. 

Using the K AM 

Photo A shows the front panel. From left to 
right: 



HEADSET JACK 
NORM/REV 

NORM/WEFAX 



KAM/HS 



REC/X MfT 



(P10) 

(St) Switches RTTY 

between HF and VHF, 

(52) Switches the HF audio to 
the VHF port of the K AM 
for WEFAX. 

(53) Switches the HF receive 
and transmit from the 
KAM to the headset 

<S4) Switches PTT. 



Photo B shows the connectors on the back 
panel. From left to right: 



on my next box I should add another audio 
input in the back panel for my scanner. Other- 
wise. I've got what I wanted. It's nice to 
switch to WEFAX and tune up and watch the 
scan and then later drop over onto the RTTY 
repeater and rag-chew for awhile. And, of 
course, the KAM excels in packet. All this 
with just the Hip of a switch or two! These 
alterations have made a very nice operating 
interface just a little more friendly. 



Joe Davidson N4AQG has been a fiam since 
1976, and is especially interested in lOni SSB 
and FM DXing. Joe currently works as a 
technical advisor in avionics and tactical 
radio for the Department of the Army, Other 
interests include computer hacking and 
landscape painting with acrylics. You may 
contact him at 1863 Mount Berry Drive, 
Douglasvitle* GA 30135. 



REMOTE PTT 


(P1) For a remote switch, e.g. 




foot switch. 


VNF DB-9 


(P2) (Female) connects the 




KAM VHF port to the 




switch box. 


HFD&9 


(P3) (Male) connects the KAM 




HF port to the box. 


VHF AUDTO 




IWOUT 


(P4) Alternative to using 




the "Y* 1 cables that come 




with the KAM. 


HFAUD tQ IN/OUT 


' (P5) As above, for HF 


VHF AFSK 


(P6) Transmit audio for VHF, 
(P7) To VHF rig. 


VHF PTT 


HFAF5K 


(P8) Transmit audio for HF. 


HFPTT 


(P9) To HF rig. 


Almost Perfect 

Anor iirinn if r/sr *i fjoiu yl-iiji- I i\ri*<-\ riasl that 



Satellite Tracking 

with your PC and the Kansas City Tracker 0* Tuner 
























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The Kansas City Tracker is a hardware and software package that connects between your rotor controller and an IBM XT, AT, or 
clone It controls your antenna array r letting your PC track any satellite or orbital body The Kansas City Tracker hardware 
consists of a half size interface card that plugs into your PC It can be connected directly to a Yaesu/Kenpro 5400 A/ 5 600 A rotor 
controller It can be connected to other rotor assemblies using our Rotor Interface Option. 

The Kansas City Tuner is a companion product thai is used til satellite work It can provide automatic doppter-shift compensation 
for digital satellite work The Tuner is compatrble with most rigs including Yaesu. Kenwood, and Icom It controls your radio thru its 
serial computer port (if present) or through the radio's up down mic-ctick interface 

The Kansas City Tracker an*\ Tuner include custom serial interfaces and do not use your computer's valuable GOMM ports The 
software runs in your PC's "spare time/' letting you run other programs at the same lime. 

The Kansas City Tracker and Tuner programs are Terminate-and-Stay-Resident" programs that attach themselves to DOS and 
disappear You can run other DOS programs while your antenna tracks its target and your radios are tuned under computer control 
This unique feature is especially useful for digital satellite work; a communications program like PROCOMM can be run while the PC 
aims your antennas and tunes your radios in its spare time Status pop-up windows allow the user to review and change current and 
upcoming radio and antenna parameters The KC Tracker is compatible with DOS 2 00 or higher and wilt run under DESQ-VIEW. 



Satellite and EME Work 

The Kansas City Tracker and Kansas City Tuner ire fullv 
compatible with AMSATs QUIKTRAK (3 2) sin6 wrth Silicon 
Solution's GRAF IRAK (2 0) These programs can be used to load 
I he Kansas City Tracker's tables with rnore than 50 satellite 
passes We also supply assembled St tested TAPR PSK modems 
with cases and 1 lOv power supplies 

DX. Contests, and Nets 

WoffcirH) DX ot contests and nwd ihre*? hands? Use I* - Kansas 
City Tracker pop up IO work your antenna rotoi for you The 
Kansas City Tracker is compatible with all DX Inyying 
programs A spei lal callsian aiming program is included for 
working nets 

Packet BBS 

The Kansas City Tracker comes complete with special control 
programs that allow the packet BBS user or control -op to perform 
automated antenna aiming over an hour, a day. or a week Your 
BBS or packet station can be programmed to automatically solicit 
mail from remote packet sites 

Vision-Impaired Hams 

The Kansas City Tracker has a special morse-code sender 

Section that will announce the rotor position and status auto 
mattcaily or on request The speed and spacing of the code are 
ittl|usiab1e 



The Kansas City Tracker and Tuner packages include the 
PC interface card, interface connector; software diskette, and 
instructions. Each Kansas Cuy unit carries a one year warranty 

9 KC Tracker package for the Yaesu Kenpro 

5400A/5600A controller 

• Interface cable for Yaesu Kenpro 

5400A 5600A 



1 J H 1 I 



Rotor Interface Option (to connect to 
ANY rotors) 



$ 30 



• KC Tuner Option ............. $ 79 

• Assembled & tested TAPR PSK modem with case & 



1 10v power supply 



A MS AT QuikTrak software 



i ) ■ i t- *• 



$219 



$ 75 



Visa and MasterCard accepted 

Shipping and handling $5 $20 for international shipments 

Prices subject lo change without notice 

L. L. Grace 

Communications Products 
41 Acadia Drive • Voorhees, NJ 08043 • U S A 

For more info Telephone 609-751 -101 8 

CompuServe 72677 1 107 



Number 1 6 on your Feedback card 



Packet Radio and 

High-Tech 

Nomadics 



A sneak preview of 
the Winnebiko ill. 

by Steven K. Roberts N4RVE 



If you've been reading 73 for over a year, 
you've already had a look at the Win* 
nebiko II— the computerized, ham radio- 
equipped recumbent bicycle that I've pedaled 
1 6,000 miles around the United States. And if 
you were a regular reader of my article se- 
ries, you even might have wondered what 
happened; I've received a few pieces of pack- 
et mail asking if I* ve been run over by a truck . 
Well, if I've been struck by anything at all, 
it's the passion to create new machines, Mag- 
gie KA8ZYW and I are currently in a year- 
long Silicon Valley layover, building all-new 
bike systems and preparing to hit the road for 
many years of open-ended international trav- 
el. The project has been escalated to a new 
level, with the design specification now 
calling for maximum independence from 
support facilities of any kind. Indeed, this has 
become an all-out effort aimed at creating a 
self-maintaining mobile information plat- 
form, constantly in communication with 
worldwide voice and data networks while 
freely wandering the Earth's surface under 
human and solar power. 

Winnebiko III Architecture 

Packet radio is a key component in the 
system, but before a description of its imple- 
mentation can make sense, you need a quick 
look at the whole machine. One disclaimer: 
This is an overview of work-in-progress, and 
there may be a few discrepancies between 
what is stated here and what actually rolls out 
the door this winter. 

There arc two major electronic areas in the 
new machine. Up front in the streamlined 
console are all computer and control systems, 
and back in the solar-roofed trailer are the 
rackmount ham shack and power manage- 
ment hardware. Between the two sit the wet- 
ware information system and bio-engine, 
coupled to the rest of the machine via a vari- 
ety of interfaces that include a heads-up dis- 
play, ultrasonic head-position sensor for dis- 
play control, speech I/O, handlebar 
keyboard, active Peltier-effect scalp-cooling 
system, thumb mouse, and random controls. 
Oh yes— and pedals, 

48 7$ Amateur Radio • October. 1989 




Steve Roberts N4RVE on the Winnibiko IL Tin* new 

recumbent, the Winnibiko III, will carry both the PacComm 

Micropower-2 TNCandthe MFJ 1278 multi-mode data 

com roller. Apart from "traditional" pocketing* Brian will 

be a roving PBBS> and use a packet link to remotely 

control the bike *s computer/radio system from a laptop, 



The controller for the whole machine (one 
level down from the human, that is) is an 
eminently hackable CMOS 68000 running 
FORTH, It's in charge of the local area net- 
work that connects all other information sys- 
tems and 68HC11 microcontrollers, as well 
as a giant ** resource bus" based on Mitel 
crosspoint switches and AMD programmable 
gate arrays, Through this array pass all au- 
dio, serial, power-control and status signals, 
making it extremely easy to establish connec- 
tions between subsystems that I might not 
originally intend to interface, Also in the con- 
sole system are a pair of DOS environments 
for AutoCAD, OrCAD, mapping, satellite 
tracking, text editing, database management. 



"The controller 

for the whole machine Is 

an eminently hackable 

CMOS 68000 running 

FORTH/' 



and communications. On top of this there'll 
be a significant new machine, still propri- 
etary, that I'll reveal in a later article, as well 
as a dedicated 68HC1 1 for data collection and 
a few stand-alone intelligent devices for navi- 
gation, speech, and so on. 

All this provides extensive real-time 
processing horsepower and a very friendly 
user interface— with a VGA backlit display, 
a 640 x 200 LCD for the FORTH, a flip-down 
hi-res screen, and the heads-up display as 
graphics options. But now that I can compute 
as much as I want, how do I communicate 



with the rest of the world? 

The trailer system carries the bulk of the 
radio gear (not including the cellular phone, 
the 56-kilobaud spread-spectrum data link, a 
Swintek full-duplex wireless intercom for se- 
curity monitoring, and an embedded ICOM 
\i2 AT in the console for bike-to-bike chat). 
The radio gear takes the form of a shock- 
mounted 19" equipment rack accessible 
through a fold-down rear door, along with a 
collapsible antenna mast for the OSCAR- 13 
array and whips, a permanent 70cm collinear 
for Microsat operation, and the usual bag of 
dipoles and accessories. 

The rack-mounted gear includes ICOM's 
new 725 (modified for low-power drain), a 
pair of Yaesu multimode transceivers for 
both OSCAR and terrestrial VHF/UHF oper- 
ation, a pair of ARR preamps. an AEA ATV 
transceiver, an antenna tuner and coax patch 
panel, an MFJ/Bencher keyer, a power-entry 
module for AC line interface to the bike's 12 
volt bus, a regenerative braking controller, 
yet another 68HC 1 1 for trailer data col lection 
and local control, and two of the bike's three 
main batteries. Maggie's bike, incaseyou're 
wondering, carries a Vaesu 290 and Ranger 
3500 for 2 meter and 10 meter multimode 
operation. 

But where does packet fit in all this? 

Bicycle Datacomm 

For the last three years I've been running 
bicycle-mobile packet via PacComm's first- 
generation TNC\ the bike's computer, and 
the handlebar keyboard. This has been a fair- 
ly low-level manual operation, with a few 
tentative stabs at maintaining a mobile BBS, 
but no real autonomy in the datacomm and 
message-passing realms. 

The new system is different, and uses pack- 
et in three ways. 



First, I carry both a PacComrn Micro- 
power-2 and an MFJ 1278 for "traditional" 
packet radio use. The MFJ multimode unit, 
modified with all SMOS components to 
minimize power drain, is for browsing the 
HF spectrum in search of interesting FAX, 
RTTY, and AMTOR contacts. The 35 mA 
PacCorrvm is For 2 meter packet and has a big 
FET switch on the modem disconnect to 
accommodate a TAPR PSK demodulator for 
the Microsacs. In both cases, operation is via 
the handlebar keyboard and any of the display 
spaces when Vm mobile, or via a laptop when 
I'm parked. 

The difference between mobile and parked 
operation has spawned the second major 
packet addition to the system. Last time, the 
robust machine was my laptop, and the 
on-board computer was fairly wimpy. With 
that setup, I had no particular interest in using 
the bike machine when parked, and happily 
immersed myself in the H-P system instead. 
But now the bike's Ampro 286 with a 40- meg 
hard disk and 4-mcg RAMdisk (along with 
other extensive processing resources) makes 
carrying a high-end laptop seem a bit 
unnecessary. The problem* however, is that I 
don't particularly want to sit on the bike 
working for hours when I'm not actually 
riding it. 

The solution is simple. A pair of PacComrn 
surface-mount TNCs — one on the bike and 
one in my backpack— are linked to each other 
via 2 wall Maxon business-band UHF data 
radios (which require a separate license). 
When Fm off the bike, the only hardware left 
active is this data Link and a security system. 
If 1 want to access bike resources for any 
reason 1 1 can fl ip open the backpack , bring up 
a communication program, ami sign on from 
up to three miles away. 

The first level of response from the bike is 
the mini-PBBS in the PacComrn, which, un- 
like the typical TNC, lets me send a data 
packet that writes directly to a parallel port, A 
keyword docs the trick, booting up the 68000 
system through a power controller and pre- 
senting me with its FORTH command line. I 
now have full control of the system and can 
check telemetry data, dial out via cellular 
phone, boot up the 286 and access a database, 
power up and operate the ICOM 725, or send 
speech strings for local output via the Au- 
dapter speech synthesizer. The whole bike, 
except for the wheels, is completely remote- 
controlled. . for everything is computer- 
controlled. 

The third major packet application on the 
Winnebiko III involves the orbiting BBSs 
scheduled for launch this November — AM- 
SAT*s quartet of Microsats, The details will 
clarify as the system comes together, but pre- 
liminary discussions indicate that wherever 
in the world we travel, my bike will periodi- 
cally run a satellite tracking program, power 
up the Yaesu system at the appropriate times, 
scan with the TAPR demodulator's feedback 
until the bird is acquired, then automatically 
exchange text files and upload the latest block 
of telemetry data (including our precise loca- 
tion derived from GPS satellites). All this 
will be piped through "mission control' in 



the States, with the data parsed and retrans- 
mitted to other nodes as appropriate, It seems 
likely that this will become a significant com- 
ponent of my non-business E-mail traffic— 
and provide a spirited demo of Microsat tech- 
nology: a guy wandering the world on a 
bicycle easily tracked to within a few hundred 
feet from someone's ham shack. 

Fellow hams, we have some amazing tech- 
nology in this subculture of ours! 

The PR Component 

I'd like to make a quick comment on a 
related issue. Recent discussion on both wire- 
line and packet nets has revealed the dis- 
turbing fact that the new director of the FCC 
is Sharree Marshall, an ex-employee of the 
law firm that has represented UPS in its suc- 
cessful bid for the 220-222 MHz portion of 
the amateur spectrum. 

We hams have more of a problem than 
ever. The days of taking spectrum space for 
granted are quickly passing, as alluring new 
technologies compete for consumer dollars. 
The UPS crisis is just the first obvious loss; 
there are a lot of people out there (and I know 
some of them) who want— and will aggres- 
sively fight for — our space. We have a few 
advocates in high places* but not enough , and 
we can no longer assume that someone will 
take care of the problem for us. 

One contribution that every ham can make 
is public relations, I'm doing some by inte- 
grating ham radio into a high-tech, upbeat 
lifestyle and writing about it for non-ham 
publications. Others can score PR points by 
fixing public problems, getting school kids 
excited, passing traffic to world trouble 
spots, inventing nifty gizmology and making 
it clear that it grew out of ham radio, publish- 
ing callsigns with technical papers, and gen- 
erally doing anything possible to bring our 
image into the current century. 

Yes, it's all image, just like any other kind 
of marketing, It may af times seem blatant 
and artificial, but that's how the world works. 

Here's the test: Take an average person off 
the street, expose him or her to a few minutes 
of typical repeater chatter and HF commen- 
tary about weather and equipment, then pose 
the question, "Which is the better use of a 2 
MHz piece of the spectrum, improving the 
speed and efficiency of your UPS deliveries 
or giving these guys more room to talk to each 
other?" Until that average person springs to 
our defense with the very arguments we've 
been making to each other for the last 50 
years, we have a problem. 

This article is ostensibly about bicycle- 
mobile packet, so with that timely little 
diatribe about the future of ail this equipment 
I'm pedaling, I'll close. As the next few 
months pass, you'll be hearing from me in 
growing detail about the new systems, until 
we're finally on the road and on the 
air again. . .where we belong. 

73 de N4RVE 



Steven K, Roberts N4RVE r author of Com- 
p uting Across Ame rica and features in 73 
Magazine, can he reached at 1306 Ridgeway 
Ave. , New Albany IN 471 50, 




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73 Amateur Radio • October. 1989 49 



Number 1 7 on your Feedback card 



Improve your TNCs DCD circuit 

Make your DCD faster and more discriminating. 



by Eric Gustafson N7CL 



Proper data carrier detection 
(DCD) is one of the most impor- 
tant items to consider on any multiple 
access packet channel. The DCD cir- 
cuitry for nearly all currently available 
TNCs are deficient for use on a radio 
channel Some are better than others , 
but most can be dramatically im- 
proved. This article shows yoti how to 
do jusi thai! 



Purpose of DCD 

The DCD's main function in the 
TNC modem is to prevent transmis- 
sion on an occupied channel. If two 
stations transmit at the same time, a 
collision occurs, which corrupts ihe 
data, which means both stations have 
to re-send the data. This increases the total 
load on the channel and reduces throughput 
for everyone. 

What's the optimum DCD circuit for pack- 
et radio? It should have these five key fea- 
tures; It must reliably distinguish information 
from noise: it must transmit packet data unin- 
hibited by an open squelch; its signal should 
remain valid through momentary fades or 
collisions: it should tolerate signal level dif- 
ferences: and it must be fast. 

The last item is most important. Most cur- 
rent TNCs rely on the rig's squelch to keep 
noise out of the modem, Many squelches, 
however, open very slowly. During that 
time, the TNC may decide to transmit even 
though someone else has started using the 
channel. 

Existing Methods 

There arc two principal ways TNCs detect 
a data carrier on the channel — phase correlat- 
ed DCD and total audio power based DCD. 
The first type is inexpensive and easy to use, 
and is of two primary types. One looks for 
phase correlated signal power in the audio 
presented to the demodulator; the other, ap- 
plied after the data decision, looks for regular 
transitions in the data stream emerging from 
the demodulator. A good example of the use 
of this second type of circuit is the K9NG 
9600 bps modem. (For more information, see 
L * Modifying the Hamtronics FM-5 for 9600 
bps Packet Operation/ by Steve Goode 
K9NG, in the ARRL Amateur Radio Fourth 

Computer Networking Conference, pages 
45-5 U 

The TAPR TNCs use the output of the 
in-phase channel phase detector of the phase 
locked loop (PLL) in an XR22I l demodula- 
tor to look for power in the incoming audio 
that is in phase with the tracked FSK signal. 

50 73 Amateur Radio • October, 1989 











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Photo A. The state machine DCD circuit prototype. 

Audio signal components (noise) in quadra- 
ture phase relation to the tracked signal do not 
contribute any average power to the detector 
output signal. This type of detector has a 
dramatically reduced sensitivity to noise. 

The total power based DCD circuit, based 
on total audio power going to the demodula- 
tor, simply measures the total energy in the 
modem pass band. It assumes any signal is a 



data signal. These circuits are appro- 
priate only for telephone systems 
which are usually very quiet in the 
absence of the desired signal. 

Either of the two-phase correlated 
DCD methods is far superior to the 
total power methods in the radio envi- 
ronment. Both have the ability to reli- 
ably indicate the presence of a data 
carrier, while being able to ignore high 
amplitude noise that may be present 
when the desired signal is absent. This 
characteristic is important because an 
unsquekhed FM receiver typically 
produces "pink" audio noise whenev- 
er the signal is absent. This noise is 
considerably higher in amplitude than 
the desired signal. 
Apart from the MFJ-1278, 1 am not aware 
of any ham packet TNCs that have modems 
with DCD circuits optimized for the radio 
environment. 

Modifying Popular TNCs 

It's not hard to make a DCD circuit that 
operates in accordance with the above points. 
If you have a TNC that uses either the 



DATA IN 



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Figure I. Improved DCD circuit. 




Photo B. The TAPR state machine DCD kit, 

AMD7910 or the TCM3105 single chip 
modem, or if you have a TNC that uses a 
modem based on audio filters like the PK- 
232, you can vastly improve the DCD per- 
formance of your modem for packet radio. 
These units all rely solely on total signal 
power with NO phase correlation as a basis 
for the DCD decision. The circuit in Figure 1 
gives a phase correlation based DCD with 
"hang" for these TNCs, 

How It Works 

The DCD circuit presented here is based 
on the update signals in a digital phase 
locked loop lDPLL) t which recovers both 
baud clock and data from an NRZI packet 
data stream. Its output represents detection 
of baud clock phase correlation with the 
transitions in the demodulator output data 
stream. 

The circuit consists of the state machine 
that TNC-2 uses along with some delay ele- 
ments used to make the DCD decision. The 
74HC374 and the 27C64 chip form the state 
machine. The 74HC14 is used as a pair of 
reiriggerabte delay elements, and for signal 
inversion and buffering, Paul Newland AD7I 
originally wrote the slate machine code used 
here and in the TNC-2s + 

You can get the 27C64 with the state ma- 
chine code already burned into it directly 
from TAPR. This same code is in the state 
machine ROM in any full TNC-2 clone using 
the XR221I demodulator and Z80 SIO. If 
present in the TNC, it will be labeled 
"STATE 1 .09." 

One of the state machine signals (which 
was not used in the TNC-2) appears on pin 1 9 
of the 27C64, This signal is the DPLL update 
pulse. As long as die DPLL is correctly 
locked to the incoming data, no pulses appear 
on this pin. When the DPLL is not locked to 
an incoming data stream, a continuous stream 
of pulses appear on it. 

This circuit uses the DPLL update signal to 
ret rigger the first delay element so that it 
never times out when DPLL update pulses 
arc present. If the pulses disappear, the delay 
element times out and generates the DCD 
signal. 

The output from the first delay element 
keeps the second delay element triggered so 
long as DCD is true. When DCD goes false, 
the second delay element begins a time-out 
sequence that keeps the DCD output true until 
the time-out period expires. This is the source 
ol' the DCD "hang time." 

While the circuit here is mainly intended 
for 1200 baud VHF FM operation, it also 



works well for 300 baud HF packet work. If 
you're on 300 baud HF packet, you'll have to 
increase the lime constant of the "hang" gen- 
erator (0,47 |iF cap) to about 2 (iF. The time 
o instant optimum for the DCD generator (the 
n 1 [xF cap in Figure I ) depends on a number 
of factors, including the bandwidth of the 
radio used ahead of the modem. 

Pick a value for the DCD generator delay 
capacitor that produces about a 10 percent 
duty cycle of false DCD ON time, while 
monitoring receiver noise on a channel that is 
absolutely free of any signals falling within 
the demodulator's passhand. This value will 
probably be two to four times the 0.1 \\F 
value used for 1200 baud. 

Both negative true and positive true DCD 
output are provided so you can use the polar- 
ity your TNC requires. Also, JMP1 and 
JMP2 let you configure the DCD circuit to 



operate correctly from either a positive or 

negative true CD output from whichever 
modem chip your TNC has. 

Build the circuit in Figure 1 on as small a 
piece of perf board as possible. You can then 
interface it to the TNC and mount it to one of 
the large chips with double-sided foam sticky 
tape, Photo A shows the original prototype of 
this circuit, mounted in a PK-87. 

TAPR has a kit available to case this mod. 
The kit costs S 1 7. 50. (Tucson Amateur Pack- 
et Radio P.O. Box 22888. Tucson AZ 85734- 
22888) Photo B shows an assembled TAPR 
state machine DCD kit circuit board. 

TNC Signals 

Once you've built the DCD circuit, you 
need to obtain some signals from your TNC 
for the new DCD circuit to use. You'll also 
have to arrange for the output of this circuit to 



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CIRCLE 194 ON READER SERVICE CARD 



73 Amateur Radio • OctobeM969 51 



be substituted for the normal DCD signal the 
TNC uses. 

DCD circuit operation requires the follow- 
ing signals: 

1. A s«imple of the data the demodulator 
recovered in the modem. 

2. A sample of a clock that has a frequency 
of either 16 or 32 times the baud rate. 

3. The intercepted carrier detect (CD) sig- 
nal from the modem. This is the CD the 
modem generated based on amplitude of the 
input audio. 

4. A source of +5 volts. If you use all 
CMOS parts, current requirements arc mini- 
mal. The 74HC14 MUST be a CMOS part 
for the circuit to work properly, 

5. Ground- If your TNC has a provision 
for a TAPR-style modem disconnect header, 
it can easily locate and conveniently interface 
these signals (including the X 16 or X32 baud 
clock) at this header. If it doesn't have this 
header, you 11 need to fish around in the cir- 
cuit of your TNC to find them. In any case, 
you will have to disconnect the DCD signal 
currently used in your TNC and reroute it 
through the new circuit. 

Standard Header Signals 

The signal locations on the TAPR standard 
modem disconnect header are as follows: 

1. Receive data is obtained from header 
pin 18. 

2. Carrier detect is obtained from header 
pin 2, 

3. Data carrier detect (DCD) is inserted at 
header pin I , Jumper from header pin I to 
header pin 2 is removed. 

4. The baud clock is obtained from header 
pin 12. The frequency of this clock will be 
cither 32 or 16 times the haud rate, depending 
on whether you have a TNC-1 or one of two 
types of TNC-2. No changes are necessary to 
use either clock speed, 

AM7910 and TCM3105 Connections 

The signals of interest on the AMD7910 
modem chip are: 

1. Receive Data output (RD)— pin 26. 

2. Carrier Detect (CD)— pin 25, (This sig- 
nal is negative true for the 7910 chip.) 

The signals of interest on the TCM3105 
modem chip are: 

1. Receive Data output (RXD)— pin 8. 

2. Carrier Detect (CDT i— pin 3, {This sig- 
nal is positive true for the 3 105 chip.) 

3. In TNCs that use the TCM3105 chip, 
but do not provide another source of the baud 
clock like the Kantronies KAM, you can use 
the signal at pin 2 of this chip. This signal is 
very close to 16 times the baud rate (19.11 
kHz instead of 19,2 kHz for 1200 baud). 

AEA PK-87 

tfs easy to interface the new DCD circuit 
to the PK-87, You don't have to switch back 
to the internal DCD circuit once you install 
the mod. 

The data signal comes from the center pin 
of JP4, and the carrier detect signal from the 
end of JP5, which connects to the modem 

$2 73 Amateur Radio * October, 1989 



chip. Insert the DCD output signal from the 
new circuit at the center pin of JP5, and use 
the negative true output. Remove the jumper 
originally installed at JP5, The DCD indica- 
tor on the front panel will show the action of 
the new DCD circuit. 

The X32 baud clock signal comes from pin 
13 of U20 (a 74LS393 divider). Don't be 
tempted to get this signal from the "clock" 
line on J4, the external modem connector, as 
this is an X 1 clock. 

AEA PK-232 

This data controller is also easy to interface 
to the new circuit. The receive data signal is 
at the center pin of JP4. and the carrier detect 
signal at the end of JP6, which is NOT con- 
nected to pin 3 of the external modem connec- 
tor. The X32 baud clock signal comes from 
pin 13 of U8 (also a 74LS393 divider). 

Insert the DCD output from the new circuit 
at the center pin of JP6. Use the negative true 
output. Then remove the jumper originally 
installed at JP6. 

To use the new DCD circuit with a PK-232 
on VHF 1200 baud FMr 

1 , Set the audio level from the radio so that 
the tuning indicator "spreads" fully on the 
station with the lowest transmitted audio level 
on the channel, 

2. Set up the DCD threshold control so that 
the DCD indicator LED on the front panel 
lights up whenever there is ANY signal or 
noise inpul to the TNC from the radio. Be 
sure that even the station with the lowest 
amount of audio on the channel lights this 
LED. This LED should go out when there is 
no audio input from the radio {dead carrier 
from repeater, for example). 

If you want to see the action of the DCD 
signal that the new circuit generates, add a 
high efficiency LED and Ik series resistor 
between +5 volts and the LED output of the 
new DCD circuit. The anode end of the LED 
should go toward + 5 volts. 

Thanks to AEA, who recently provided for 
the detection of a DCD fault condition (usual- 
ly improperly set threshold control) in the 
PK-232 TNC software. If you have an older 
PK-232, contact them for the ROM upgrade. 

Pac-Comm TINY-2 

The Pae-Comm TfNY-2 hooks up as 

follows: 

The X 16 baud clock signal is at U 10, pin 1 . 

Receive data is at J5, pin 17. 

Negative true carrier detect (CDT) is at J5, 
pin 2. 

Note; This is an inverted version of the CD 
output from ihe TCM3105 chip itself. Since 
this is a negative true logic signal, JMP1 on 
the new DCD circuit will be used instead of 
JMP2, which would normally be used for a 
TCM3I05. 

Negative true DCD from the new circuit is 
applied to the TNC at J5 pin 1 . Remove the 
connection between JS pins 2 and I. The 
existing DCD indicator LED will not show 
the action of the new circuit, 

If you want to observe the action of the 
DCD signal that the new circuit generates, 



add a high efficiency LED and Ik series resis- 
tor between +5 volts and the LED output of 
the new DCD circuit. The anode end of the 
LED should go toward +5 volts. 

If you want to observe the action of the new 
DCD circuit on the existing LED indicator, 
you will have to do the interface a bit differ- 
ently. First, you get the negative true CDT 
signal from pin 1 of JPD- Then insert the 
LED output signal from the new circuit at 
cither pin two of JPD or pin two of J5* Re- 
move the jumper currently installed ai JPD on 
the TINY-2 circuit board. Early versions of 
this unit may not have JPD. If the new circuit 
is interfaced in this manner, you can no 
longer use the "RFDCD" signal. (This is no 
great loss, however, as it will also no longer 
be necessary.) 

Kantronics RAM 

The RAM design makes it impractical 
to correct the behavior of the DCD circuit 
of the 300 baud modem. For 1200 baud 
operation, these are signal location points of 
interest: 

The receive data (RXD) signal is at pin 8 of 
[he TCM3105 modem chip. 

The X 1 6 baud clock signal is at pin 2 of the 
TCM3105. 

The positive true carrier detect (CDT) sig- 
nal from the modem is at pin 3 of the 
TCM3105. This line from the modem to the 
CPU is labeled with two numbered pads (7 
and 8), which represent pin numbers on a 
20-pin modem disconnect header physically 
similar to. but electrically dissimilar to, the 
standard TAPR modem disconnect header. 
You should use JMP2 on the new DCE circuit 
to break the connection between these two 
locations. 

The DCD output from the new circuit is 
injected at pin 21 of the 63B03 CPU. The 
front panel LED that normally indicates CDT 
signal activity w ill show the action of the new 
DCD circuit. 

Conclusion and Thanks 

This article describes desirable character- 
istics in a TNCs DCD circuit. The modifica- 
tion instructions enable owners of most 
TNCs to upgrade their units. 

1 would like to express appreciation to 
those who helped with this project, Many 
thanks to Lyle Johnson W A7GXD, who con- 
verted the prototype designs to printed circuit 
boards for the TAPR kits. This will save 
many people a lot of effort in performing the 
conversion on their TNCs* My thanks to 
Mykle Raymond N7JZT, who built the pert 
board prototype of the slate machine DCD 
circuit. This prototype was used to tune the 
values of the delay timers. He also volun- 
teered his PK-87 for testing. And thanks to 
Dan Morrison K V7B, who proofread the arti- 
cle and provided much useful technical ad- 
vice. 



Contact Eric Gustafson N7CL at 2018 S. 
Avenida Planeia, Tucson AZ 85710. See the 
follow-up to this article— improving DCD in 
XR2211 based TNCs— -in an upcoming issue 
of 13. 



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73 Amateur Radio • October. 1989 53 



Number 1 8 on your Feedback card 



TexNet 
Packet-Switching Network 

An overview of a highly successful 
and efficient packet radio network. 



by Greg Jones WD5IVD 



Conceived by Tom McDer- 
moll N5EG and Tom 
Aschenbrenner WB5PUC in the 
summer of 1985, the Texas net- 
work began as a small summer pro- 
ject. One year later, the result was 
TexNei— an inexpensive, multi-re- 
source, four-port, high-speed 
"backbone,* 1 datagram- based am- 
ateur packet switching system. 
TexNei allows Texas packet radio 
operators to communicate effec- 
tively over distances of several 
hundred miles in real time, and is 
currently believed to be the longest 
and fastest 9600 baud amateur net- 
work in the United States (see Fig- 
ure 1 1. 



Mi* mm _ 




u. 




IJL 



Photo B 
sar. Mic 



System Definition 

TexNeu a datagram-based net- 
work, acknowledges packets at 
each step of the path, operates with 
minimal lime delay, and provides 
user services as well as information 
about network operations. Opera- 
tion is at 9600 baud on 450 MHz, 
with typical local user access at 
1200 baud AFSK on two meters or 
220 MHz. If necessary, inter-node 
trunks can run at any of the lower 
speeds, and the primary or sec- 
ondary user port will support other 
baud rates and modulation techniques. 

The system is completely compatible with 
both versions of the AX, 25 protocol specifi- 
cations for user connections. The network 
itself communicates between its own nodes 
using AX . 25 as the data-link layer two proto- 
col and TEXNET-IP as the layer three net- 
work protocol. The TEX NET- IP protocol 
adds only five bytes of overhead to the front 
of every packet inside the network. 

TEXNET-IP is transparent to all users 
because the entry and exit nodes translate 
the users 1 packets to TEXNET-IP and back 
again (see Figure 2), The terminating nodes 
during a user connection maintain tables that 
specify how each user is connected. 

The purpose of an intermediate node is to 
perform transit- routing only, A TexNet node 
operates with no fixed routing assignments; a 
node's routing table is generated upon startup 

54 73 Amateur Radio • October, 1989 



Photo A. Top view. , . 




. . . . and front panel of a TexNet Network Control Proces- 
higan TexNet Node constructed by Jay Nugent WBHTKL. 



and updated as new nodes begin operations or 
as current nodes are reset* This allows a node 
to maintain primary and secondary routing to 
all other nodes in the network (the user com- 
mand route describes this in more detail >. 
TexNet supports 255 nodes per network us- 
ing the same network ID, and there are 255 
network IDs available. 

Hardware 

The heart of a TexNet node is a partitioned 
PC board composed of the NCP (node control 
processor), a 9600 baud TPRS i Texas Packet 
Radio Society ) FSK modem, and a 1 200 baud 
AFSK modem. (Figure 3 shows a block dia- 
gram of a TexNei node configuration.) The 
third port is left free for the attachment of any 
kind of modem (land-line, 2400 baud, PSK). 
The 1 200 baud AFSK modem is similar to the 
TAPR TNC-l modem. The 9600 baud FSK 



modem is a redesigned K9NG 
modem, with improved receive fil- 
ters, The NCP unit contains a 
Z80A CPU operating at 4 MHz, 
32K EPROM, 40K RAM memory, 
two SIQ/0 serial communications 
ICs for the serial HDLC ports, and 
aCTC 

Careful design in both software 
and hardware was necessary to al- 
low all three pons to run at 9600 
bps. TPRS decided to develop its 
own board to keep the cost down 
and to include two special circuits, 
a reliable crystal oscillator and a 
fail-safe state machine called "fire 
code/ Fire code is an EPROM- 
bascd logic circuit that monitors 
the IP data and clock lines {com- 
plete! \ independent of the proces- 
sor and communications ICs) for 
the presence of a 72-bit unique se- 
quence commanding the node to 
reset. This 72-bit sequence is pro- 
grammed into the EPROM along 
I with its state machine. The mean 

^D time between false activation is cal- 

HH culated to be considerably more 

than one million \ ears. 

The local console port on the 
NCP supports the local console* 
control points, and weather inter- 
face. The control points let the 
node control and monitor status items con- 
nected to the node, Some of the uses for 
control points are to check the status of emer- 
gency power at site, to check if the power 
level of batteries is too low or too high, and to 
turn devices on and off, 

A TexNet daughterboard lets the NCP in- 
terface with an optional Winchester hard disk 
controller. The daughterboard supports the 
hard disk feature, that in turn supports the 
packet message server (PMS) and weather 
feed. The daughterboard also supports addi- 
tional control points. The local console 
weather input allows data from the National 
Weather Service to be fed in at either 1200 
bps R5-232 or 75 baud Baudot: this data is 
then stored on the PMS, 

The other key aspect of how well the hard- 
ware operates is not the TexNet hardware, 
but the backbone radio. The performance of 




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FEATURES: 

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Sends beep to telephone line, and to mobile 
indicating it's their turn to talk. 

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CW ID can be programmed using L7TMR ID 
can be programmed to be sent at the beginn- 
ing, the end, both, or not at all. 

• AUTOMATIC BUSY DISCONNECT 
Automatically disconnects if the telephone 
number dialed is busy. 

• HOOK-FLASH 

Used to make a second call without 
disconnecting and re-connecting. Also can be 
used for phone company services which use 
Hook-flash, 

• CALL WAITING 

If a mobile call is attempted and the line is in 
use, a beep is sent to the phone line indicating 
that the mobile wants to make a call Then 
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transmitted to the mobile. 

• RING-OUT (REVERSE PATCH) 

Can be programmed to ring-out one time, on 
each ring, or not at all, when the line rings. 

• SINGLE OR MULTI DIGIT CODES 
Connect or disconnect codes can be single * 
and #, or * and # plus two digits. 

• CALL LIMIT TIMER 

Can be set for 3, 4, or 5 minutes, or disabled. 
Can be programmed to reset with *. 

• MOBILE ACTIVITY TIMER 

Causes disconnect if mobile drives out of 
range. Can be set to 30, 45, 60, or 90 seconds, 

• TOLL RESTRICT 

The first digit dialed cannot be a "1" or a "O" 
Rearms after dialing is complete. 

• PHONE LINE IN USE INHIBIT 

Prevents interrupting a call when the patch 
shares the telephone line with a telephone, 

• TOLL RESTRICT DEFEAT CODE 

A special programmable code allows toll calls. 
Also allows access to line, even if line is in use. 

• TONE OR PULSE DIALING 

Switch programmable for Tone or Pulse dial- 
ing. Pulse dialing can be used on a tone line. 
- HALF DUPLEX MODE 
The VCS-2100 can be used as a repeater inter- 
connect in this mode. 



Kenwood Compatability with VCS-2100. 
All connections, required for installation 
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Amarillo 



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Dallas 1 




Paris 

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Figure /. 
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TexNet 
map. 



Raw D^i a 

IfQiTi User A 



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Ej jj j . .■...' i . 
, _ 



or 



i 



Layer 3 iSEfoO; 



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NODE A 



NODE B 



NODE C 



Figure 2, TexNet -IP layering. 



the network trunk is critical to the throughput 
of the entire network, TPRS decided to oper- 
ate TexNet trunks at 9600 baud, with rapid 
transmit/ receive (T-R) switching. At 9600 
baud, packets take relatively little time, and 
thus make the delay time of the radio between 
transmit and receive the critical factor. Com- 
mercial radios exist thai fit this criteria, but 
they require modifications. The amateur ra- 
dio community should see continued devel- 
opment of packet radius that will work better 
for higher speed digital communications, 
thus making the radio component easier to 
deal with. 

TexNet Software 

The most important aspect of TexNet is its 
software, which provides its services, 
switching, and user interface. In addition to 
access to the network, each TexNet node 
provides several services though secondary 
station IDs ( SSI Ds), 

•SSID-0: digipcater. 

•SSID-2 and 3: conference bridge. Each 
node maintains two independent conference 
bridges. Transmitted packets are sent to alt 

56 73 Amateur Radio • October, 1989 



other users connected to the conference 

bridge, providing full protocol protected 

roundtable communications. 

•SS1D-4: network access. 

•SSID-5: local node console. 

•SS1D-7: packet message server mailbox, for 

off system forwarding, 

•SSID-8 and 9: crossband digipeating. 



Connecting to TexNet (SSID-4) presents 
you with the simple TexNet network inter- 
face, that provides a straightforward way of 
using the network. All you see is data going in 
and out of the node. Upon connect, you see; 

CMD > ***cONNECTED TO WR5C4 
WR5C-4 Virtual Connection 07 at 17:04:57 
on 10/1/89 

*** Welcome to TexNet VO808-WB5PUC 

"T" "T^ "T" 

Network CMD ? (Enter H for Help) 

At the network prompt, the commands can 
be typed in completely or their First letter can 
be used. 



User Commands 

HELP lists commands. A few typical com- 
mands follow: LOCATIONS 5EHVED CONNECT 
W5ABC @, LOCATION CONNECT W5ABC VIA 
W5DEF @ LOCATION. CONNECT CQ @ LOCA- 
TION STATISTICS @ LOCATION, STATISTICS 
YESTERDAY @ LOCATION MESSAGE, and 
WEATHER BYE. 

bye disconnects you from the network. 

locations returns a table, listing all nodes 
on the network by name. 

CONNECT makes connections 
across the network. An example 
connect command is CONNECT 
WB5VZL @ Austin. TexNet at that 
point takes over; the connect re- 
quest packet is sent to the node 
named Austin, and that node at- 
tempts to connect to WB5 VZL, 

If the network node, Austin, 
makes the connection, the origi- 
nating user sees YOUR CONNEC- 
TION is established. The receiv- 
ing station. WB5VZL, will see 

•••CONNECTED TO WA5LHS-4, 

(The WB5VZL TNC shows a 
layer two connection and the call- 
sign of the Austin TexNet node.) 
Then WB5VZL in Austin will see 

**• LINKED TO WD5IVD AT NDAL- 

las via texnet. At this point, the two users 
are operating as if in simplex and the network 

maintains the connection automatically. 

If the connection is not made, the original 
ing user will see remote user not respond- 
ing, If WB5VZL in Austin were out of range 
of the network node but could be reached 
via a digipeater, then the circuit request 



ETC 




Z3 



12 



Daughter Board : 

* Ertra Node Control Pomte 

■ Pi*S - Hard Drive Interface 



Ports : 

* Use third NCP pari lor ! 

Landltne Modems. 
2nd Local Access Port 
Use other speed modems 

• NCP can support an m* ee 

ports from 1200 to 96O0OpS 



NCP 2.1 

ZB0A 4Mhz 



I 



I 



T 



9600 baud 

FSK 

Modem 



t 



1200 baud 

AFSK 

Modem 



Local Console 
■ Node Control PomiE 

* Local Console 

• Wealher Line Interlace 



l 



Low Speed 

Local Access 

Radio 



High Speed 
network Radio 



Figure 3. Block diagram of a TexNet node. 



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string would read C WB5VZL V DIGI ® AUSTIN. 

TPRS hopes that a definition and adoption 
of an inier-network or user-io-network inter- 
face standard within the amateur community 
will soon be agreed upon. 

Connections through the secondary user 
ports are also possible, You can force a con- 
nection request through a port other than the 
primary user port by appending a comma and 
the physical channel number to the node 
name, c wsabc @ ndallas.2 would force the 
conneciion request through NDALLAS's 
second user port. 

Port zero is defined us the network back* 
bone. Port one is the primary user port, 
typically 1 200 baud on two meters. The 
user pons can be 1200, 2400, 4800, 9600, 
or whatever baud the NCP board has 
been strapped for. Modulation depends 
on the modem in use. Port two can be an 
alternate user port or an alternate network 
trunk. 

connect CQ @ NODE is used to broadcast a 
CQ call over a remote node, c cq ® Austin, 
for example, transmits calling cq cq cq 

FROM WD5JVD-0 @ NDALLAS from the Austin 
node. 

The message command connects you to 
the packet message system (PMS) module. 
The network automatically routes and con- 
nects you to the node assigned as the message 
server resource for that part of the network. 
The PMS operates as a multi-connect net- 
work mailbox, as well us providing emergen- 
cy real-time transfer and store functions for 
emergency traffic operations (see the admin- 
istrative command ALERT). 

Once in the PMS system, the command 
structure is a subset of the W0RLI command 
set. The PMS is not a full service mailbox/ 
BBS system. 

The MESSAGE @ NODE command connects 
you to a packet message system at the net- 
work node indicated. This allows the network 
to support multiple PMSs at once on the 
network. 

weather connects you to the PMS that is 
designated as the weather server for the net- 
work. The network automatically routes and 
connects you to the weather node The weath- 
er data is provided through the local console 
port and is stored on disk- You list the weath- 
er products by issuing the LW (list weather) 
or LS (list server) command at the PMS 
prompt, 

statistics @ NODE returns information 
about accumulated node activity over a 24 
hour period. sy§ node accesses the stats 
from the previous day. 

ROUTE reads a node's routing table and 
outputs a tabic outlining the node numbers of 
all node names in the network, the primary 
via node, number of nodes on the primary 
path, secondary via node, number of nodes 
on the secondary path, and node name for the 
remote node. 

The path's length is weighted with a factOF 
when the network link to the listed node is 
established. Weighting is done to force the 
network to a higher speed path if one is avail- 
able and active. The weight factors are pre- 
programmed into the node's database. 

58 73 Amateur Radio ■ October, 1989 



in the alternate via path column, a node 
number of 000 indicates no secondary path. 
Aliernate routing allows automatic rerouting 
of packets past equipment failures or path 
outages, and has proven to be a valuable 
feature. You do not need to know the mutes, 
since the network keeps primary and alter- 
nate routes hidden. You use the same connect 
sequence independent of which route is cho- 
sen by the network. 

Administrative Commands 

The unlock command enables and dis- 
ables the protection on the network's admin- 
istrative commands. The most sensitive ad- 
ministrative commands cannot be issued to a 
node by the typical user. 

TIME@ NODE sets the real time clock at any 
Tex Net node. 

iNTT @ node does a complete reset of the 
TexNet node, 

A key network function is the ALERT -ON/- 
OFF @ node command. The network alen 
mode lets the network handle emergency traf- 
fic via packet radio. You can enable this 
mode from any node in the network. When an 
alert-on is issued at a node, that node sends a 
'broadcast*' command to all other nodes in 
the network, informing them that alert mode 
is active at that node. When another user 
connects to the network, he's informed that 
an alert is in progress with a command like 
the following: 

WA5LH5-4 VIRTUAL CONNECTION 03 AT 08:30:20 
ON 8/1/88 PLS DISCONNECT UNLESS YOUR TRAF- 
FIC IS RELATED TO THE NETWORK ALERT IN 
PROGRESS FROM AUSTIN. 

AH network node disconnect timers are 
disabled. A special mode of PMS is enabled, 
which provides a real-time message ex- 
change between the multiple users connected 
to the PMS. Thus, when one user sends to 
another, all the standard PMS functions are 
invoked. In addition, after saving the mes- 
sage on disk, PMS checks to sec if the ad- 
dressee is currently connected to the PMS. If 
so, PMS automatically displays the message 
at the addressee's terminal. 

PMS becomes a real-time message for- 
warding system amongst its connected users, 
with the added feature that alt messages are 
archived to die disk. This feature am be ex- 
tremely useful in emergency communica- 
tions, since the stations connected to PMS 



could be physically located anywhere along 
the network. To re-enable the timers and re- 
turn the network status to normal, the akn- 
off command is issued. 

POINT ENABLE/DiSABLE/STATUS @ NODE al- 
lows access to the control points on the NCP. 
These points can be used to monitor or affect 
items at the NCP site. 

The delete node command deletes a node 
from all routing tables throughout the net- 
work. This is used in case a route to a node 
has changed for some reason. 

Network Information Messages 

There arc two areas of node and network 
operation in which a network condition 
report or error message can occur. The 
first level of message reporting is concerned 
with conditions of the layer two data link— 
the connections between the two users* TNCs 
to the network nodes. The second stage is 
on the layer three network level— between 
network nodes. Layer three network errors 
are reported as plain text or as three- 
digit network information code (NIC), NICs 
are returned by the node affected or by 
the next adjacent node attempting con- 
nection* Network codes are three digits 
and are generated by the layer three soft- 
ware. 

TexNet Growth 

Currently, TexNet networks exist in many 
states in the United States, and nodes have 
been shipped around the world. The Oklaho- 
ma and Texas networks should be linked to- 
gether sometime in 1990, TPRS is continuing 
to work on both TexNet software and hard- 
ware development, along with an increasing 
focus as an organization on general packet 
education in Texas. 

TexNet is not the newest, fastest, or flashi- 
est of technologies, but it is reliable and flex- 
ible, and it works amazingly well. For a sum- 
mer project now in its fourth year. I would 
say it at least met, if not exceeded, its original 
design goal. 



Greg Jones ' specialities are IOmeter packet 
and CW, He works for Compaq Computer 
Corp. Greg enjoys mountain climbing and 
computer hacking. Contact him do the Texas 
Packet Radio Society. P.O. Box 831566, 
Richardson, TX 75083. 



Information 

TPRS is interested in spreading its information and research efforts as widely as possible. If you would 
like more information concerning TPRS or TexNet, please drop a letter to TPRS< PO Box 831566, 
Richardson, TX 75083. 

Sources 

Aschenbrenner, T and T. McDermott, "The TexNet Packet-Switching Network. Parts 1-3," Ham Radio, 

March, April, and June 1987, 
Horzepa, S " Yotir Gateway to Packet Radio," ARRL, 1989. 
Wade, B. T "Packet Radio Conference Bridge/' HamRa0fO. April 1987 
Jones, G, r B. Wade, and T. Aschenorenner, 'TexNet User's Manual 3.6, ,f Texas Packet Radio Society, 

February. 1989. 
Jones, G., B. Wade, andT. Aschenbrenner, "TexNet Administrators Manual 3.5, " TPRS, August, 19&8. 
T McOermott, ' 'Overview of Ihe TexNet Datagram Protocol/' Sixth ARRL Amateur Computer Networking 

Conference, ARRL 1987, p. 115. 



Number 36 on your Feedback card 



73 Review 



by Daniel Kautz WB8EHS 



DX HELPER-Version 1.3 

DX Software for the Apple Macintosh. 



DX HELPER 

Randy Siegemeyer W7HR 

POBox 1590 

Port Orchard. WA 98366 

(206)871-1111 

Price Cfass: $25 



D X Helper is designed to be a comprehen- 
_ sive DX software package, ft contains a 
great deal of information (hat is presented to 
I he DX operator in a user-friendly Mac envi- 
ronment. It's primarily intended to be used as 
a real-time "where is the DX" finder, but in- 
cludes much more than that. 

The program Selection Menu offers you 
these options: Bearing List, Distance List, 
MUF/Area map, MUF/Area/GL map. and 
Code Practice- Below this are ees£t and quit 
choices. Also available in the next menu win- 
dow is an Options Menu containing switches 
(on/off) for Gray Line, WWV (reminder), and 
Refresh (map display). 

Which Way? 

Beam heading and distance charts from 
your exact latitude and longitude (within 
one tenth of a degree) may be printed out 
as a chart using the Image Writer. There 
are two forms of map displays. These are 
displayed only on the Mac screen as a 
Great Circle map, centered on your OTH 
(Figure 1). or rectangular map form (Figure 2). 
The DX location is highlighted on either 
map with a large black dot The GL (Gray 
Line) and sun (white circle with cross 
hair) locations are updated every 10 min- 
utes (user option) on the rectangular map dis- 
play only. 

Code practice is a stand-atone extra to the 
main program. 

You can configure the scroll box to the left of 
the map to several operation modes: a DXCC 
countries list, an international prefix list, or an 
Oblast' list (USSR), The only list that works 
with the maps is the DXCC fist. The other two 
supply information in the box under the map 



area but do not place a location marker on the 
map. 

If you select DXCC for the scroll box (start 
up default) and click on a country or prefix, the 
location is shown on the world map (either 
polar or rectangular) and the following infor- 
mation is displayed under the map: 
-Latitude, longitude and zone, 
•Time difference from GMT. 
•Bearing and distance from your QTR 
•Time and date information was requested 
(GMT). 

■Sunrise and sunset (GMT), 
•3rd party traffic status (yes/no)* 
•Maximum usable frequency to that location. 
Good information for the DX hunter! 

Another excellent feature is the 24 hour 
propagation chart (Figure 3) that replaces the 
rectangular map display when you double 
click anywhere on the map, or on a country 
selection. This chart shows you the current 
time and the MUF (Frequency vs. Time) forthe 
pointer or country location chosen on the DX- 
CC map. The time line runs from midnight to 
midnight on the X axis. Frequency runs from 
to 35 MHz on the Y axis. From this you can 
determine whether conditions are getting bet* 
ter or declining for the part of the world you 
want to work. 

MUF/Area Map Generation 

After you click on the menu selection bar for 
the MUF/Area, the program requests that you 
enter the upper frequency limit, midpoint fre- 
quency, and lower frequency lirnit t in MHz. In 
the example (Figure 4), I chose 21.45 MHz 
(top of 15 meters), 18,0 MHz, and 14,0 MHz 
(bottom of 20 meters). 

The rectangular map is the only display that 



is used with this function. The program then 
begins to make 735 calculations for locations 
spaced evenly over the map display (a grid 35 
x 21). This takes about 5 minutes on my com- 
puter. 

Calculations that fall within the high to mid 
limits are illustrated as black squares. Calcu- 
lations that fall between the mid to lower limit 
are white squares, Any calculations outside 
the upper and lower limits are not illustrated. 
Setting the mid limit to the same value as the 
upper or tower limit can force only black or 
only white squares to be generated. 

There is an option in the menu bar (MUF/ 
Area/GL) for this same display, but it includes 
the gray line in the map illustration 

The maps or charts shown on the screen 
cannot be printed. However, the standard 
Mac system command < control -r shift -r 4 > 
combination will print the entire screen. 

Hone Your CW! 

Code practice sends groups of five random 
characters, with or without punctuation. 
Speed* pitch, duration (length of time code is 
sent) and volume are user-selectable. This is a 
separate program from the DX Helper win- 
dows and you must drop out of the main pro- 
gram to use this function. 

System Requirements 

The program requires a minimum 51 2K 
Mac, one 800K double-sided drive, and an 
optional (required for bearing/ distance print- 
outs only) Image Writer printer. I concur with 
the manual's statement that anyone with an 
old 126K Mac should have it upgraded to the 
new ROM* 51 2K memory, and S00K drive. My 
Mac is an original 128K and was upgraded 

continued on p, 33 



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73 Amateur Radio ■ October, 1989 59 



Number 20 on your Feedback card 



Amateur Packet Networking 



Going beyond just AX. 25 . . . 



by Brian Lloyd WB6RQN 



Amateur packet radio has been growing 
by leaps and bounds for several years 
now. The first milestone was the develop- 
ment of the TNC, followed closely by die 
creation of the BBS. Since that time relatively 
little changed until the implementation of net- 
working protocols. This article covers some 
networking concepts, explains where the 
original popular ham packet protocol, 
AX. 25, falters, and compares and contrasts 
the more popular networking protocols. 

Networking Basks 

Most publications attempting to explain 
network design use the International Stan- 
dards Organization (ISO) Seven Layer Refer- 
ence Model. This is why you hear packet 
gurus talking about the physical layer (layer 
or level one), the link layer (layer two), the 
network layer < layer three), and the transport 
layer (layer four). 

Although you may likely envision layers as 
vertically stacked* like layers of sediment in 
the earth, the Russian Matriushka doll set 
analogy is more accurate. The smallest of the 
set of dolls fits inside the next larger doll, 
which, in turn, fits inside the next larger doll. 
Likewise, in the ISO system, the raw packet 
is first bounded by bit strings that form the 
protocol for the link layer, which in turn arc 
bounded by bit strings that form the protocol 
lor the network layer, and so on up through 
the seven layers. 

Now, what distinguishes these layers? 

ISO Layers 

The physical layer is what actually moves 
data from one place to another. This includes 
hardware such as radios and modems. 

The link layer, such as AX. 2 5 protocol, is 
responsible for the point-to-point delivery of 
data, For example, if two packet stations are 
communicating through a single intermedi- 
ary, the link layer handles the packet routing 
from source station to intermediary, and then 
from intermediary to destination station. The 
link layer does not look at delivery from 
source to destination— the transport layer 
does that job. 

The network layer is responsible for rout- 
ing data through a network to the Final desti- 
nation. For example, say your packet station 

60 73 Amateur Radio * October, 1989 



uses only AX.25, and you want to connect to 
a station four hops away, with the three inter- 
mediaries all being nodes for a given net- 
working system, You first must connect to 



the first node. Then, from that node, you may 
issue the connect command for the destina- 
tion station, or to the next node, Here, the 
network layer handles your packets from the 



Virtual Circuits and Datagrams 

Another aspect to consider is whether a given network and transport 
protocol uses a virtual circuit (VC) or a datagram type of network. What is 
the difference between the two, and what are their pros and cons? 

In a VC, network packets always follow the same path and always 
remain in the same order. For this reason, once a VC path has been 
mapped out, it doesn't need to know about sources and destinations. Only 
the path identifier (known as a logical channel identifier) is needed to route 
the packets. A good analogy for the VC approach is the telephone system. 
In the phone system, you give the address once (by dialing the phone 
number) and the network establishes the connection. From then on the 
network routes the signal the same way and does not need to remember 
the actual source and destination* 

In a datagram type of network, every packet must have the source 
and destination addresses. Every time a packet arrives at a switch or 
node, Ihe destination address is examined and the switch decides how to 
route the packet. The analogy for the datagram type of network is the post 
office. Every packet is like a letter; there is a source and destination 
address on each one. The letters (packets) are dumped into a mailbox (the 
network connection) and the post office handles each one separately. If 
you have too much information to fit into a single letter, you might send it 
as several letters. Someone on the other must put the arriving letters into 
the proper order to recreate the original message and request duplicates 
for any lost letters. This sorting and retransmission request is analogous 
to the job of the transport layer. 



Best of Both Worlds 

There's a tradeoff going either way. The VC incurs less "overhead 11 — 
routing information attached to each packet — than the datagram method, 
and so keeps the throughput higher on a healthy circuit, all else being 
equal. If a part of the circuit breaks, however, VC packets are lost, 
whereas the datagram system looks for alternate paths to route the 
packets. 

AH of the above networking protocols, except KA-Node and ROSE, use 
the best of both of the above worlds, by running a VC on fop of a datagram 
network. KA-Node and ROSE are pure VC systems. 






node to which you connected, to the destin- 
ation. 

The transport layer is responsible for the 
cnd-[o-end delivery of data. 

There are three other layers above trans- 
port: session, presentation, and application 
(layers five, six, and seven, respectively). 
Here, I tump these three together under appli- 
cation, since their discussion goes beyond the 
scope of this article. 

What Layer is AX.25? 

Before the advent of networking protocols 
in amateur packet radio, AX. 25 served as 
both the link and a transport layer (and in fact 
still does in many stations today). As a link 
protocol, it ensures delivery of data only be- 
tween two directly connected stations. There 
are no intermediate nodes to worry about, so 
there is no network or transport protocol. 

On the other hand, imagine that there arc 
two digipeaters in the path between source 
and destination. Now we have intermediate 
nodes (digipeaters) and AX .25 performs end- 
to-end retransmission on either end. From 
this point of view, AX. 25 is functioning as a 
transport protocol. 

Where AX.25 Falters 

AX. 25 was never intended to operate as a 
transport protocol. It doesn't work very well 
in that capacity— more often than not, com- 
mu meat ions between two stations fails if 
there are more than two intervening 
digipeaters. 

Why? The critical point is that, with AX. 25 
as the transport protocol, any packet lost any- 
where between source and destination needs 
to be re-sent by the source. 

Assume that the packet delivery probabili- 
ty is 70^ between stations (seven out of ev- 
ery 10 packets are delivered without error). 
This is a common probability. With two sta- 
tions talking directly to one another this is not 
a serious problem. With one dig i peat er in 
between, the delivery probability drops to 
49% (0.7 x 0.7 = 0.49). With two 
digipeaters in between, there are three hops, 
and the delivery probability drops to 34% 
(0.7 x 0.7 x 0.7). Instead of seven out often 
packets being delivered, the ratio has become 
reversed; only three out often packets make it 
to the destination. 

Of course, the originating station retrans- 
mits the lost packets, but these must compete 
with the packets other stations are sending. 
You see the vicious cycle that occurs here: 
More and more retries increases the channel 
loading, which in turn increases the chance of 
collisions, which leads to further retries. The 
channel quickly suffers from congestive col- 
lapse! 

Many avid packeteers soon realized that 
networking protocols were needed: to use 
hop-by-hop ACK (acknowledgement of re- 
ceipt) packets to improve link reliability. 
(Bear in mind that there is a converse to 
this— if the delivery probability is very high. 
it is better to forego the hop-by-hop ACKs in 
favor of the end-to-end ACKs.) 

The network and transport protocols used 
in amateur packet radio all use AX. 25 as 



a link protocol between points. Some sort 
of higher level networking protocol is 
used above/around AX. 25 to perform the 
packet routing function. To date, five 
networking protocols have risen to regular 
use in amateur packet radio: K A- Node, 
ROSE, NET/ROM, TexNet, and TCP/IP. 
Let's take a look at their strengths and weak- 
nesses. 

KA-Node 

KantronicV KA-Node protocol is the sim- 
plest of all networking protocols. The user is 

responsible for manually setting up a network 
virtual circuit (see sidebar for explanation). 
To do this, the user connects to the nearest 
KA-Node and commands that node to con- 
nect to the next KA-Node. This process is 
repeated until the user commands the last 
KA-Node to connect to the destination. Three 
intervening KA-Nodes between source and 
destination require the user to enter four con- 
nect commands. 

The main advantage of KA-Node is that 
it uses AX. 25 connections between each 
node to improve the reliability of the end- 
to-end connection. The other advantage of 



a 



- . - It is 



possible to make 

Net communicate 

with all (other popular 

networking systems) 

and act as a gateway 

between these 
different networks. " 



KA-Node is that it comes as pan of all 
Kantronics TNCs so you don't have to pay 
extra for it. 

There are two disadvantages to KA-Node: 
user complexity , and no end-to-end transport 
layer. It takes a good deal of typing for a user 
to set up a KA-Node connection to a remote 
station. Also, if any intervening connection 
breaks, the whole end-to-end connection is 
broken, without the source having any 
knowledge of what actually got through to the 
other end, 

ROSE 

The RATS Open System Environment (a 
ROSE by any other name) is a full implemen- 
tation of X.25 and TPI— two common com- 
mercial protocols— for a TNC. AX. 25 is ac- 
tually a slight modification of something 
catled Link Access Protocol Balanced 
(LAPB), the link layer protocol from X.25. 
Some people within RATS decided that it was 
a good idea to complete the ISO OSI protocol 
stack and implement X.25 and TP I (transport 
protocol number 1 ). The result is a ROM for 
the TNC-2 that turns it into a real virtual 
circuit packet switch. 



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73 Amateur Radio * October. 1989 61 



The major advantage of ROSE is that it is 
available from RATS at little or no cost (the 

software is available on numerous bulletin 
boards if you can bum your own ROMs) and 
it will work with almost any TNC-2 compat- 
ible TNC. ROSE also eliminates the KA- 
Node requirement to send a connect com- 
mand to each successive node between source 
and destination. The user connects with the 
nearest ROSE switch and then tells it to con- 
nect to the final destination, using a special 
country /city code which identifies where the 
destination can be found. From then on. con- 
nection establishment and maintenance is au- 
tomatic, 

ROSE shares the major disadvantage of 
KA-Node; a disconnect anywhere along the 
line breaks the entire link to the destination. 
In spite of this, ROSE is an interesting pack- 
age that deserves your attention if you have a 
TNC-2, 

NET/ROM 

NET/ ROM has been around for about two 
years. The company Software 2000 original- 
ly offered it as a plug-in ROM for any TNC-2 
compatible TNC. 

To use NET/ROM, a user connects to his 
local NET/ROM, command the local NET/ 
ROM to connect to the NET'ROM nearest 
the desired destination, then command the 
remote NET/ROM to connect to the actual 
destination. All intermediate links use AX.25 
to improve reliability. 

NET/ROM has some neat features. Every 
NET/ROM periodically broadcasts all NET/ 
ROM nodes that it knows about. Other NET/ 
ROM nodes hear these broadcasts and for- 
ward the information in their own broadcasts. 
In this way, the information about all the 
NET/ROM nodes propagates around the net- 
work. 

NET/ROM works quite well, but it, too, 
has its limitations. For example, the NET/ 
ROM broadcasts assume that if station A can 
hear nation B\ nodes broadcast, then A can 
route data through B. Unfortunately , this is 
not always the case, the result being network 
dead ends. 

Another technical problem is that each 
NET/ROM node must keep a list of all 
the other NET/ROM nodes in the net- 
work. This is fine when the network is rela- 
tively small, but it becomes unwieldy when 
the network gets large. A TNC-2 has only 
32K of memory, which is not easily expand- 
ed, and the node tables take up precious 
space. 

The last technical problem is that the NET/ 
ROM network layer does not provide 
for other transport layers besides the stand- 
ard NET/ROM transport layer. This 
becomes a problem when you try to do inter- 
network (connect different kinds of net- 
works), 

Finally. NET/ROM is not inexpensive at 
about $60 per ROM, plus you have to buy 
NET/ROM all over again to get the upgrades. 

Fortunately, there are options that avoid 
the price. There are other programs that are 
fully NET/ROM compatible, but arc clearly 
independent of NET/ROM . The First of these 

62 73 Amateur Radio * October, 1989 



is PC/Node* written by John Wiseman 
G8BPQ. 

PC/Node and TCP/IP 

PC/Node runs on any IBM-PC compatible 
computer and provides fill I NET/ROM capa- 
bility. PC/Node can make use of TNCs run- 
ning the KISS (Keep It Super Simple) proto- 
col (most TNCs have this capability), or it 
can work with an internal packet card, such as 
the DRSI PC*Paeket Adapter or the Pac- 
Comm PC- 1 00. PC/Node also supports ei- 
iher a W0RL1 or a WA7MBL BBS running in 
the same machine, 

The second option is the KA9Q TCP/IP 
program, KA9Q TCP/IP contains an imple- 
mentation of the NET/ROM protocol, but it 
does not include the capability for users to 
connect with their TNCs. The NET/ROM 
function of the KA9Q Net program can serve 
as an intermediary and as a destination node 
for a NET/ROM network, but not as a termi- 
nation node tor such a network. In other 



"The first 

milestone was 

the development of 

the TNC, foil owed 

closely by the 

creation of 

the BBS/ 9 



words. Net supports only NET/ROM to 
NET/ROM packets. Even though it is not a 
complete implementation, it is quite nice for 
backbone network nodes where there are no 
end users, 

TexNet 

Unlike the other networking packages de- 
scribed here. TexNet is a complete hardware/ 
software system, A TexNet node includes a 
Node Control Processor, 9600 baud back- 
bone radios, 1200 baud user access radios, 
the network software, and a number of appli- 
cation software packages. 

TexNet is interesting because, in spite of its 
simplicity, it works vei> well. It provides 
access from user-to-user and user-to-BBS. In 
addition, many of the TexNot nodes offer 
weather data and personal messaging. 

Technically, TexNet is similar to, but not 
compatible with, NET 'ROM, The Texas 
Packet Radio Society's choice to offer a com- 
plete system keeps the cost down. The 
TexNet network is a joy to use because it is 
fast and reliable. A TexNet node is less ex- 
pensive than a two-port NET/ROM node, 
and you gel high-speed (9600 bps) backbone 
trunks in the bargain, 

TCP/IP 

TCP/IP stands for Transmission Control 

Protocol/Internet Protocol. Originally devel- 



oped for the Defense Department TCP/IP is a 

well-thought-out collection of protocols, 
TCP/IP was the mainstay networking proto- 
col for government and experimental packet 
radio long before there was amateur packet 
radio. 

The key to TCP/IP is the Internet Protocol. 
As the name suggests, IP is designed to inter- 
connect different networks. In the commer- 
cial and eovernment world IP is used to inter- 
connect local area networks, dedicated 
telephone links, public packet switching net- 
works, and packet radio networks. It does 
this by hiding the differences between the 
networks* 

In amateur packet radio. TCP IP was writ- 
ten by Phil Kam KA9Q PhiKs "Net" pro- 
gram implements TCP/IP and several associ- 
ated applications for keyboard QSOs, file 
transfer, and electronic mail, Net has also 
been a springboard for others to add function- 
alits to. NtM now supports the user iniorma- 
tioo service called Finger, and it supports 
NET/ROM. Both of these functions were 
written by others and integrated into the Net 
package. 

One of the problems all the other network- 
ing packages have is that they arc not compat- 
ible with one another, ROSE can't communi- 
cate with NET/ ROM, NET/ROM cant 
communicate with TexNet, and TexNet can't 
communicate with ROSE t etc, On the other 
hand, it is possible to make Net communicate 
with all of them and act as a gateu a\ between 
these different networks. Already Net 
supports TCP/IP over NET/ROM, and there 
is talk of support for TCP/IP over TexNet 
and possibly TCP/IP over ROSE, Net is fast 
becoming the universal packet radio pro- 
gram! 

Net is available for IBM-PC compatible 
computers, the Commodore Amiga, the 
Atari 520, the Apple Macintosh, and most 
UNIX™ based computer systems. About the 
only thing it doesn't run on is the Com- 
modore-64. You can get Net from TAPR for 
the cost of disk duplication (SI per disk at last 
accounting). 

Conclusion 

Real-live networking is available now. All 
you have to do is to choose your favorite 
flavor. AH of the networking packages have 
their advantages and disadvantages. It is my 
view, however, that the KA9Q Net package 
stands above the rest because of its universal- 
ity. It does AX, 25 "traditional packet.' 
NET/ROM. and TCP/IP all at once* TexNet 
is probably the most complete system with 
everything in one package. NET/ROM and 
ROSE are interesting because they allow you 
to turn your existing digipeaters into network 
nodes with a minimum of fuss, Happy net- 
working! 



Brian Lloyd WB6RQN has pursued amateur 
radio enthusiastically since age eight. He re- 
cently co-founded Sirius Systems, a network- 
ing business in Petersburg. Virginia. You 
mav reach Brian at: 5712 StiBwelt Rd.. 
RockvilteMD2085L 



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73 Amateur Radio * October, 1 989 63 



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64 73 Amateur Radio • October, 1989 



Number 21 on your Feedback card 



DXDA '89 

The Dynasty Grows . . . 

73 Magazine welcomes the new members to the growing DX Dynasty Award 
cadre! Special thanks to DXDA chairman Bob Reed WB2DIN for processing the 
results. Congratulations to all for a job well done. 



First 


OneHundre 


d Award Endorsements 


150 


NK62 


100 All SSB 


212 


FD1BEG 


100 All SSB 








151 


KB6IUA 


100 150 Mixed 


213 


DU1DZA 


TOO All 15m SSB 


12 


WD5N 


250 Mixed 


152 


W90KH 


100 All SSB 


214 


N81MZ 


100 150 All SSB 


19 


N6CGB 


200 All SSB 


153 


WB5FXT 


100 150 All SSB 


215 


KK4YA 


100 All SSB 


43 


VE6VK 


150 Mixed 


154 


NB3E 


100 All SSB 


216 


LU1JDL 


100 All SSB 


50 


K8MDU 


250 All SSB 


155 


N2ESP 


1 00 All SSB 


217 


KA9YYZ 


100 All SSB 


68 


KFSPE 


100 All CW 


156 


YV2EJU 


100 150 200 All SSB 


218 


KA4TMJ 


100AII10mSSB 


72 


IK8GCS 


200 300 All SSB 


157 


OZ1 DXX 


100 All CW 


219 


WAflDDC 


100 Mixed 


73 


WB4I 


150 AH SSB 


158 


IK5IIU 


100 150 AH SSB 


220 


YC1CIS 


100AH15mSSB 








159 


KA1ION 


100 150 All SSB 


221 


YC3FNL 


100 150 All SSB 


New Awards and Endorsements 


160 


KD3AI 


100 All SSB 


222 


GBFWG 


100 150 All SSB 








161 


OK1AEH 


100 All CW 


223 


KV4B 


1 00 Mixed 


101 


K5AOB 


100 AH SSB 


162 


W9LCR 


100 All SSB 


224 


N5IET 


100 All SSB 


102 


KW2D 


100 Alt CW 


163 


8P6SH 


100 ALL SSB 


225 


WA9WIG 


1 00 Mixed 


103 


PY3ARZ 


100 All SSB 


164 


KA6SPQ 


100 150 All SSB 


226 


N3CDA 


100 All SSB 


104 


WB4ETD 


100 All SSB 


165 


ZF2KH/ZF8 


100 All SSB 


227 


KE6KT 


100 150 All SSB 


105 


N2FPB 


100 150 All SSB 


166 


W6MVV 


100150 All SSB 


228 


IK7DBB 


100 All SSB 


106 


KD3CQ 


100 All SSB 


167 


JA8CAO 


100150AI1CW 


229 


JY5EC 


100 Alt SSB 


107 


K4NNK 


100 Mixed 


168 


KI6WF 


100 150 All SSB 


230 


N1ETT 


100 All 10m SSB 


108 


VU2DNR 


1 00 AH 20m SSB 


169 


K2MRB 


100 Mixed 


231 


PY2DBU 


100 Mixed 


109 


AA5BE 


100 All SSB 


170 


AA6GM 


100 All CW 


232 


181 YW 


100 All SSB 


110 


PYSOG 


100 Mixed 


171 


JA0SU 


100 150 Mixed 


233 


N0ISL 


lOOAIMOmSSB 


111 


VE4ACF 


200 All SSB 


172 


NU8Z 


100 All SSB 


234 


KC4BEB 


100 All 10m SSB 


112 


VE4SI 


100 Mixed 


173 


G0GRK 


100 Alt SSB 


235 


WA7QQI 


100 All SSB 


113 


PJ2KI 


100 Ail SSB 


174 


YB0VM 


100 Alt 20m SSB 


236 


KA1RJG 


lOOAIMOmSSB 


114 


WB4CKY 


100 All SSB 


175 


DV1BRM 


100 Mixed 


237 


OZ9BX 


100 150 All CW 


115 


W6EOB 


100 Mixed 


176 


WBTU 


100 Mixed 


238 


KB4HBH 


100 All SSB 


116 


KK4IY 


100 All SSB 


177 


N7CNH 


100 All SSB 


239 


KA3RWP 


100 All 10m SSB 


117 


IK1YU 


100 150 All SSB 


178 


PY3IO 


100 All SSB 


240 


NJ1T 


1 00 150 Alt 20m CW 


118 


N8GCN 


100 All 20m SSB 


179 


YB0ZCA 


100 All SSB 


241 


W4DCG 


100 All SSB 


119 


KB1AF 


100 Mixed 


160 


YB0AF 


100 All SSB 


242 


YCQRX 


100 All SSB 


120 


KBSBHE 


150 Mixed 


181 


VE3PQB 


100AIICW 


243 


VE70J 


100 All 20m SSB 


121 


KE2CG 


100 150 200 250 All SSB 


182 


W2SV 


1 00 1 50 All SSB 


244 


AA4W 


100 Mixed 


122 


VS6CT 


100 All SSB 


183 


N1ADE 


100 Mixed 


245 


N9GMM 


100 All SSB 


123 


G3IZQ/W1 


100 150 All SSB 


184 


WP4AFA 


100 150 All 20m SSB 


246 


KB4HBH 


100 All SSB 


124 


WB6FNI 


100 All 80m SSB 150 


185 


KS7V 


100 Mixed 


247 


KM4HF 


100 All SSB 






All SSB 


186 


W20FB 


100 All 20m CW 


248 


CE1YI 


250 All SSB 


125 


KAWAR 


100 All SSB 


187 


G4ASL 


100 All CW 


249 


KA1FVY 


100 All CW 


126 


K9SM 


100 Mixed 


188 


N5JUW 


100 Mixed 


250 


N2GVB 


lOOAIMOmSSB 


127 


W6BCQ 


100 150 Ail SSB 


189 


KA8WAS 


100 All SSB 


251 


N2DAO 


lOOAIMOmSSB 


128 


KA5MSL 


100 Mixed 


190 


5N0WRE 


100 150 200 All SSB 


252 


WF8E 


100 Mixed 


129 


WB4FLB 


100 All SSB 


191 


AA4IP 


100 Mixed 


253 


YB0HZL 


150 All SSB 


130 


N7GLT 


100 All SSB 


192 


JR5KDR 


100 All SSB 


t3^ 


N5MBD 


100 AH SSB 


131 


WA0X 


100 All SSB 


193 


KD2WO 


100 150 All SSB 


255 


N4SNS 


100 All SSB 


132 


KF4GW 


100 All SSB 


194 


KA3NIL 


100 Mixed 


256 


KA3TGY 


lOOAIMOmSSB 


133 


N4QGH 


100AlM0mSSB 


195 


WA8YWK 


100AIICW 


257 


JN3XLY 


150Ali15mSSB 


134 


VE1CBK 


100 Ah SSB 


196 


VE1ACK 


100 150 All CW 


258 


N4PUV 


lOOAIMOmSSB 


135 


7J1AAL 


100 All SSB 


197 


HP2XVB 


100 All SSB 


259 


KA9MRU 


150 All SSB 


136 


K6ICS 


100 All SSB 


198 


WB5KYK 


100 Mixed 


260 


KA40TB 


100 All SSB 


137 


NZ7W 


100 Mixed 


199 


N5JUJ 


100 150 All SSB 


261 


N4JED 


100 All SSB 


138 


WBGN 


100 All 20m SSB 


200 


N40BJ 


100 All SSB 


262 


AB4KA 


100 Mixed 


139 


WC7F 


100 Mixed 


201 


9Q5NW 


100 150 Mixed 


263 


WA70ET 


1 00 Mixed 


140 


F6IFE 


100 150 200 All SSB 


202 


KW2D 


100 All 20m CW 


264 


KA3RVH 


lOOAIMOmSSB 


141 


KL7N 


100 Mixed 


203 


VE1HA 


100 All CW 


265 


CE7ZK 


250 AH SSB 


142 


KE8LM 


200 All SSB 


204 


HP8BSZ 


100 All SSB 


266 


NI9J 


100 Mixed 


143 


WA6YOO 


100 All SSB 


205 


IK5JJG 


100 All SSB 


267 


WB9PTN 


100 All SSB 


144 


VE2MFD 


100 150 Mixed 


206 


YC3DKN 


1 00 All 1 5m SSB 


268 


KB8DAE 


200 AIM Om SSB 


145 


N3APQ 


100 All SSB 


207 


I3VKW 


100 150 200 All SSB 


269 


W0CL 


100 All SSB 


146 


HK1D80 


100 All CW 


208 


K2EWA 


100 All SSB 


270 


WB7VUB 


lOOAIMOmSSB 


147 


NM3V 


100 All CW 


209 


KD3CR 


100 150 All SSB 


271 


JF6TU 


100 AIM 5m CW 


148 


IK6GFY 


100 Mixed 


210 


N9GDG 


100 All SSB 


272 


ZY3IO 


100AIISS6 


T49 


WB6UAN/M 


100 AH 10m SSB 


211 


KF8K 


100 Mixed 


273 


KB4VIR 


lOOAIMOmSSB 














73 Amateur Radio 


* October, 1989 65 



Official DX Dynasty Countries List: 8/1/89 



ABU AIL 


A15 


FINLAND 


OH 


MARION ISLAND 


. . , ZS2 


SENEGAL , , , 


6W 


AFGHANISTAN 


YA 


FRANCE 


F 


MARKETREEF 


OJG 


SERRANABANK 


. . HK0 


AGALEGA ISLAND 


■ at ■ fr\ 

3B6 


r 1 ini^Vw . . . - 

FRANZ^IOSEF LAND 


UA1 


rf 1 rl ■ 111 ^v n 11 ^h ^mt 1 r t. t p • ■ ■ ■ 1 

MARQUESAS ISLAND 


. FOS 


SEYCHELLES 


S79 


ALAND ISLANDS 


OHt 


FRENCH GUIANA 


..FY 


MARSHALL ISLAND 


■ ■ m m V ■ J 


SICJLY , 


IT9 


ALASKA 


KL7 


FUTUNA ISLAND 


FW 


MARTIM VAS ISLAND 


py§ 


SIERRA LEONE 


. . "I__ 


ALBANIA 


ZA 


GABON . . 


TO 


MARTINIQUE 


FM 


SINGAPORE 


9V 


ALOABRA ISLAND 


S79 


GALAPAGOS ISLAND 


HC& 


MAURITANIA 


5T 


SINT EUSTAT1US 


PJ 


ALGERIA 


■ ■ ■ ■ ■ i i i ¥ W% 


linMBIn 1 . . ■ < 


C5 


MAURITIUS ISLAND . 


........ . . 3o0 


SJNT MAARTEN ISLAND 


PJ 


AMERICAN SAMOA . 


ksq 


GEORGIA 


UF 


MAYOTTE 


FH 


SMOM 


1A 


AMSTERDAM ISLAND 


FT-Z 


GHANA 


9G 


M E XICO ............... 


At 


SOCIETY ISLAND 


F06 


ANDAMAN ISLAND , 


VU4 


GIBRALTAR 


ZB2 


MIDWAY ISLAND 


KH4 


SOCOTRA ISLAND 


709 


ANDORRA 


C3 


GLOHIOSO ISLAND 


FR/G 


MINAMI TORI SHIMA 


JD1 


SOLOMON ISLANDS 


H44 


ANGOLA 


D2 


GOUGH ISLAND 


ZD9 


MINERVA REEF 


A3 


SOMAU REPUBLIC 


T5 


ANGUILLA 


VP5E 


GOZO ISLAND 


9H4 


MIQUELON ISLAND 


■ r 


SOOTH AFRICA . 


ZS 


ANTARCTICA 


KC4 


GRAHAM LAND 


VP0 


MOLDAVIA 


UO 


SOUTH GEORGIA ISLAND 


VPB 


ANTIGUA 


V2 


GREECE 


sv 


MONACO 


3A 


SOUTH ORKNEY ISLAND 


VPB 


ANTIPODES ISLAND 


ZL 


GREENLAND 


ox 


MONGOLIA 


JT 


SOUTH SANDWICH ISLAND . 


VPB 


ARAN ISLAND 


. . EJ0 


GRENADA 


J3 


MONTSERRAT 


VP2M 


SOUTH SHETLAND ISLAND 


VPB 


ARGENTINA 




GUADELOUPE 


FG 


MOROCCO . 


CN 


SOUTH YEMEN 


70 


ARMENIA . . 


p W 4 p f T m m f—f. 4 1 la^VJ 


GUAM , ,..,.. 


KH2 


MOUNT ATHOS ...... 


SY 


SPAIN . 


EA 


ARUBA 


PJ4 


GUANTANAMO BAY 


KG4 


MOZAMBIQUE 


C9 


SPRATLY ISLAND 


ts 


ASCENSION ISLAND 


2D6 


GUATEMALA 


TG 


MY AN MAR {BURMA) . 


XZ 


SRI LANKA 


4S 


AUCKLAND ISLAND 


ZL9 


GUERNSEY 


GU 


NAMIBIA 


ZS3 


ST BRANDON ISLAND 


3B7 


AUSTRALIA 


VK 


GUINEA ... 


3X 


NAURU 


C2 


ST HELENA ISLAND 


ZD7 


AUSTRIA 


OE 


GUINEA-BISSAU 


m 


NAVASSA ISLAND 


KP1 


ST KITTS . 


V44 


AVES ISLAND 


wa 


GUYANA 


ART 


NEPAL 


9N1 


ST LUCtA 


J6 


AZERBAIJAN 


UD 


HAITI 


HH 


NETHERLANDS 


PA 


ST MARTIN ISLAND 


...FS 


AZORES ISLANDS 


. .. cua 


HAWAII ........... 


KH6 


NETHERLANDS ANTILLES 


. . P J 


grr paul island 


FT8 


BAHAMA ISLANDS 


QB 


HEARD ISLAND , 


VKfl 


NEVIS ISLAND ... 


V47 


ST PETER AND PAUL HOCKS , . 


PY6 


BAHRAIN 


A9 


HONDURAS 


HR 


NEW CALEDONIA 


■ r ■ ■ w V 4 * ff\ 


ST PIERRE AND MIQUELON ISLANDS FPS 


BAKER ISLAND 


KHT 


HONG KONG 


VS6 


NEW HERBHIDES 


YJ 


ST VINCENT 


J8 


BALEARIC ISLANDS 


EAS 


HOW LA NO ISLAND 


KH1 


NEW ZEALAND 


ZL 


SUDAN 


ST 


BANABA 


T33 


HUNGARY 


HA 


NEWFOUNDLAND 


VOi 


SUMATRA 


YB 


BANGLADESH 


S2 


ICELAND 


TF 


NICARAGUA 


YN 


SURINAM 


PZ 


BARBADOS 


6P 


IFNI 


EA9 


NICOBAR ISLAND 


VU4 


SVALBARD ISLAND 


JW 


BEAR ISLAND 


JW 
ON 


INDIA 

INDONESIA 


VU 
. YB 


NIGER 

NIGERIA 


, . . . 5U 


SWAN ISLAND 

SWAZILAND 


HR0 


BELGUIM 


5N 


..., 3DA« 


BELIZE , 


V3 


IRAN 


. ,.EP 


NIUE ISLAND 


ZK2 


SWEDEN 


SM 


BENIN . 


Tv 


IRAQ 


... Y1 


NORFOLK ISLAND 


VK9N 


SWITZERLAND 


HB 


BERMUDA 


VP9 


IRELAND 


EL 


NORTH KOREA . 


P5 


SYRIA 


T W% 


BHUTAN 


AS 


ISCH1A 


IC 


NORTH YEMEN 


4W 


TAOZHIK 


UJ 


BOLIVIA 


CP 


ISLE OF MAN 


GO 


NORTHERN IRELAND 


Gl 


TAIWAN 


8V 


BONAtRE 


. PJ9 


ISRAEL 


4X 


NORWAY 


...LA 


TANZANIA 


. . . . . Jjr»i3 


BON1N 


JDi 


fTALY 


.1 


OGASAWARA ISLAND 


JD 1 


TASMANIA 


VK7 


BOP H UTHATSWAN A 


H5 


IVORY COAST 


TO 


OKINO TORI SHI MA \ BALDWIN' S REEF) ?J 


THAILAND 


HS 


BOTSWANA 


A2 


JAMAICA 


6Y 


OMAN 


A4 


TINIAN 


Km 


BOUNTY ISLAND 


. ZL 


JANMAYENiSLAND 


JX 


PAKISTAN 


» ■. -rtr 


| L^iPUk^ j ■ tt * ■ <•>'* ■ -1 4 9 '*-* » ■ 


.... 5V 


BOVFT ISLAND 


. 3Y 


JAPAN , 


JA 


PALMYRA ISLAND 


KH5 


TOKELAU .. 


ZM7 


BRAZIL 


PP-PY 


JARVIS ISLAND 


KH5 


PANAMA 


HP 


TONGA ISLAND 


A3 


BRITISH VIRGIN ISLA 


NDS VP2V 


JAVA 


YB 


PANTELLERIA ISLAND 


IH 


TRANSKEI 


.. . S8 


BRUNEI 


VS 


Jcnbci 


GJ 


PAPUA NEW GUINEA 


P2 


TRANSVAAL 


T4 


BULGARIA . 


U 


JOHNSTON ISLAND 


KH3 


PAHACEL ISLANDS 


BY 


TRINIDADE ISLAND 


PYf 


BURKINA FASO 


XT 


JORDAN 


JY 


PARAGUAY 


ZP 


TRINIDAD AND TOBAGO 


9Y 


BURUNDI 


9U 


JUAN DE NOVA ISLAND 


FR/J 


PERU 


OA 


TRISTAN DA CUNHA . 


... ZD9 


BYELORUSSIA 


uc 


JUAN FERNANDEZ ISLAND 


-CEft 


PETER 1ST ISLAND 


3Y 


TROMEUN ISLAND 


FRrr 


CAMEROON 


T J 


KALININGRAD . 


UA2 


PHILIPPINES 


DU 


TUAMOTU ARCHIPELAGO. ... 


FOB 


CAMPBELL ISLAND 


ZL9 


KAMARAN ISLAND 


VS9 


PHOENIX 


T32 


1 '_Jl.iL/rM ......j.-.l.--. . .. . * ■ * 


. . . . . . . r L/o 


CANADA 


VE 


KAMPUCHEA 


XU 


PITCAIRN ISLAND .... 


VRfi 


TUNISIA. . 


3V 


CANARY ISLANDS 


EAS 


KAZAKH 


UL 


POLAND ...... 


J"* 


TURKEY 


TA 


CAPE VERDE ISLAND 


S D4 


KENYA 


52 


PONZ1ANE ISLAND 


IB# 


TURKMEN 


UH 


CAPRJ ISLAND 


IC 


KERGUELEN ISLAND 


FTX 


PORTUGAL 


CT 


TURKS AND CA*COS ISLANDS 


.... VPS 


CAYMAN ISLANDS 


ZF 


KERMADEC ISLAND 


ZL9 


PRINCE EDWARD ISLAND 


... VEt 


TUSCAN ARCHIPELAGO 


1A 


CEDROS ISLAND 


XF1 


KIRGHIZ 


UM 


PRINCE EDWARD ISLAND 


ZS2 


TUTUILA ISLAND 


KHB 


CELEBES , 


YB 


KOREA 


HL 


PRINCtPE 


SS 


TUVALU 


T2 


CENTRAL AFRICAN F 


IEPUBLIC . . . . TL 


KURE ISLAND 


KH7 


PRIBILOF ... 


KL7 


UGANDA. fci , 


SX 


CENTRAL KIRIBATI 


. T3 


KUWAIT 


, yK 


PHOVIDENCfA ISLAND 


HK0 


UKRAINE ................ H , . 


UB,UT,UY 


CEUTAANDMELILLA 


... EAS 


KWAJAL2IN 


KX6 


PUERTO RICO 


KP4 


UNITED ARAB EMIRATES ... 


■ ■■■■■•■ #\u 


CONWAY REEF 


3D2 


LABRADOR . . 


V02 


QATAR 


A7 


UNITED NATIONS-NEW YORK 


4U1UN 


COUNCIL OF EUROP 


E TP2 


LACCAOIVE ISLANDS 


VU7 


RAPA ISLAND 


...... HJo 


UNITED NATIONS-GENEVA 


4LHTU 


CROZET ISLAND 


FT-W 


LAMPEOUSA ISLAND 


IG 


REPUBLIC OF CISKO 


...... , Ml 


UNITED NATtONfrVIENNA 


... 4U1VC 


CURACAO 


PJ 


LAOS 


XW 


REUNION ISLAND 


FR 


UNfTED STATES . 


W.K.NA 


CYPRUS 


&B4 


LATVIA 


UO 


RE VILLA GIG EDO ISLAND 


XF4 


URUGUAY 


CX 


CZECHOSLOVAKIA 


OK 


LEBANON 


OD 


RIODEORO 


EAS 


UST1CA ISLAND 


IE9 


DENMARK 


. OZ 


LESOTHO 


7P 


ROCKALL ISLAND 


„.„;, gm 


UZBEK 


in 


DESECHEO ISLAND 


. KP5 


LESSER ANTILLES 


PJ 


RODRIGUEZ ISLAND 


3B9 


YMlNlJH 1 1-/ . . T . 1 


YJ 


DES ROCHES 


VQ9 


LEVANZO ISLAND 


IF9 


ROMANIA , 


YO 


VATICAN CITY .,.. 


HV 


DIEGO GARCIA 


VQ9 


IBERIA 


EL 


RONACDORCAY ...„ 


....... nixv 


VENEZUELA 


YV 


DJIBOUTI 


J? 


LIBYA 


5A 


ROTA ISLAND 




VtETTNAM 


3W 


DODECANESE ISLAN 


DS SV5 


LIECHTENSTEIN 


HBQ 


ROTUMA ISLAND 


302 


VIRGIN ISLANDS 


)S*j£ 


DOMINICA 


J7 


UNE ISLANDS 


T32 


RUSSIA-SIBERIA 


UAM 


WAKE ISLAND 


KH9 


DOMINICAN REPUBL 


IC HI 


LITHUANIA 


UP 


RUSSIAN S.F.SR 


UA 


WALES 


GW 


EAST CAROLINE ISU 


^NOS K06 


LORD HOWE ISLAND 


VK2 


RUSSIAN URAL MT 


....... UA9-» 


WALLIS ISLAND 


..... FW 


EAST GERMANY 


Y2-Y4 


LUXEMBOURG 


LX 


RWANDA 


........ Ija 


WALV1SBAY 


ZSG 


EAST KIRIBATI 


T32 


MACAO 


XX 


RYUKYU ISLAND 


JR6 


WAYNE GREEN 


. . W2NSD 


EASTER ISLAND 


CE® 


MACQUARIE ISLAND 


VK9 


SABA ISLAND 


PJ 


WEST CAROLINE ISLAND 


V63 


ECUADOR 


HC 


MADAGASCAR 


5R 


SABAH 


--.,>* 9Mb 


WEST GERMANY 


DL 


EGYPT 


SU 


MAOD ALENA ISLAND 


IM 






WEST KIRIBATI 


T3 


EL SALVADOR 


YS 


MADERA ISLAND 


CT3 


SABLE tSLAND ...... 


VE1 


WESTERN SAMOA 


5W1 


ENGLAND 


G 


MALAWI 


TQ 


SAJPAN 


KHi 


WESTERN SAHARA 


SI 


EOUATORLAL GUINE 


A 30 


MALAYSIA .. 


9M2 


SAKHALIN ISLAND 


UA9-t 


W1LUS tSLAND 


. . . . VK9Z 


ESTONIA 


UR 


MALDIVE ISLANDS 


60 


SAN ANDRES ISLAND. 


HK* 


WORLD BANK , 


4U2 


ETHIOPIA 


£T 


MALI 


TZ 


SAN FELIX ISLAND ... 


CEflX 


YEMEN .. 


4W 


EUROPA ISLAND 


FR/E 


MALYjAfYSTOSKUfM-V) ISLAND .. 


... 4J 


SAN MARINO 


17 


YUGOSLAVIA 


YU 


FALKLAND ISLANDS 


VPS 


MALPELO 


HKffl 


SAO TOME 




1 \J rV^-'l^l ■ ■ 1 ■ ■ n r ■ • 1 ■ I....II... 


VY1 


FAROE ISLANDS 


... OY 


MALTA 


9H 


SARAWAK 


9M8 


ZAIRE 


...... 1 _ 3U 


FARQUHAR 


V09 


MANIHIKI 


ZK1 


SARDINIA 


IS 


ZAMBIA 


9J 


FERNANDO DENORC 


3NHA PY«F 


MARCUS ISLAND 


JD 


SAUOtA ARABIA 


HZ 


ZANZIBAR 


5Ht 


FU] ISLANDS 


3D2 


MARIANA ISLAND 


KH2 


SCOTLAND 


...... GM 


ZIMBABWE 


... Z21 



66 73 Amateur Radto • October, 1989 



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73 Amateur Radio • October, 1989 67 



Number 22 on your Feed bach card 



TCP/IP 
for the Macintosh 

Now this powerful PC runs one of packet radio 's 

hottest networking systems! 

by Doug Thorn N60YU and Dewayne Hendricks WA8DZP 



There is a new voice in packet radio 
known as ihe TCP/IP, TCP/IP can 

provide hams with many new features and 
capabilities never before seen in amateur ra- 
dio packet communication. Implemented on 
the Macintosh, these features are easy to use 
and understand. 

TCP/IP Protocols 

TCP/IP (Transport Control Protocol/Inter- 
net Protocol) is a set of protocols developed 
in the 70s for use with ARPANET* a network 
of computers used by the Department of De- 
fense, Today tens of thousands of computer 
systems in the world use TCP/IP because it 
id lows normally incompatible systems to 
communicate with each other. Typically, 
TCP/IP is implemented on large mainframe 
and mini-computers, and has not been avail- 
able to the personal computer user, Phil Karn 
KA9Q was challenged several years ago to 
implement it on his PC. His co-workers said 
it couldn't be done. . . . The result was the 
KA9Q Internet Protocol Package, now avail- 
able for several major personal computers. 
Phil's effort has now made it possible for the 
average ham who has a computer in his shack 
to use these protocols for packet. 

Why TCP/IP? 

Packet radio started out before the personal 
computer really put its mark on John Q. Pub- 
lic. Early use was purely for keyboard-to- 
keyboard contacts, later evolving into the 
PBBS (Packet Bulletin Board System) net- 
work that exists today, 

TCP/IP provides a basic framework onto 
which you may add services. An example 
is Telnet protocol, that provides keyboard- 
to-keyboard communications, just like tradi- 
tional packet. Another example is FTP (File 
Transfer Protocol), that implements a simple 
file transfer system between stations. SMTP 
(Simple Mail Transfer Protocol) provides 
mail services. All of these protocols run at 
the same time, allowing several people to 
connect to your station at once. As you can 
see, each of these are separate, and you can 
easily add new commands as the system 
evolves. By using the TCP/IP protocols, we 
now have the ability to interoperate with 
these tens of thousands of computers on many 

68 73 Amateur Radio • October, 19B9 



of the world's networks, not just on packet. 

Net/Mac and BM/Mac 

One of the major advantages the Macintosh 
provides is the consistent user interface. This 
means we don't have to learn lots of new 
commands to become proficient with any 
program. However, this requirement to sup- 
port an "ease of use* 1 interface has caused 
some difficulties in our attempt to get Phil's 
package to run cm the Macintosh. 

One of the major issues we had to over- 
come was the conversion of NET and BM 
(the names given to Phil's programs) into 
Net/Mac and BM/Mac and make ihem into 
modeless programs. In the Macintosh world, 
all programs are modeless. This means that 
the user can perform any action at any time, 
regardless of the current state of the program. 

For example, Phil's implementation has a 
command line orientation. A user enters one 
command after another to cause the program 
to perform a given set of actions. In Macin- 
tosh programs we can perform additional 
functions, such as opening desk accessories 



(calculator, alarm clock, editor, etc) togeth- 
er with cut-and-paste, between programs at 
any time. 

In bringing KA9Q TCP/IP to the Macin- 
tosh, we tried to preserve the command line 
interface while keeping traditional Macintosh 
functions. This resulted in ahvbrid form: one 
familiar to the typical Macintosh user, while 
preserving some of the look and feel of the 
original version. 

What It Does 

The Mac offers the major advantage of 
on-screen, multiple-sessions at the same 
time. Every time the user creates a new ses- 
sion, such as an FTP, a new window is creat- 
ed for that session where all of the input and 
output will appear. The session most recently 
created becomes the active session. The user 
can switch between sessions by either select- 
ing the desired session from the "^Window" 
menu or by clicking on the session window 
with the mouse. 

The console session window is the only 
session window active when the program is 



* File Edit Windows 2130 Jg 






Finger - n6oyu 




Name : UftVHE GREEN 1 1 




License W2NSD License Cross: A 




Mail address: UGE CENTER, PETERBOROUGH , HH Q345B-Q000 




Station address: RT 202 AMD FOREST RO f HRNCQCX, NH 




Effective date Rug 11, 198? Expiration dote: Aug 11, 1397 




Prev i ous Co 1 1 s t gn : Preu i ous C t ass : 




Sirthdote Sep 3, 1922 Process date: Rug 11, 1987 




Trace - anO 




RX25: N60VU->KJ6QR 1 NR*2 NS=2 pid=Text 




0000 License UD6GYH License Class: A, 




axO recv 




RX25 KJ60fi->N80VU RR<P> MR=1 




axO sen t 




RX25 N60VU->KJ6QR RR(F) NR=2 

1 




rnnsnlp =^^^^===^^^^=^^^^^^=^^^^^^=^ 


net> finger ffw2nsd?n&ouu 




net* 




Vou're being fingered by 44 4 t 209 1008' (Sun Jul 16 14 29:09 1989) 




net> 






B 



Figure I. A typical screen with three windows. Hie top window shows the results of a callsign 
query, the middle window shows a trace of TNC and computer activity, and the last window is 
the command console. 



f 

6 Fife Edit LJJinrJoujs 


12:01 fi 




- 


~~^^^^^^^~ ^^^~~ ~ ■— v | v -^ w^^^^^^^^h^^^^^^^^^^^^^^h 


; ^^_^^_ 


SVM sent 






Eat obi iahed 






220 rcOVU.norcal cmpr.org FTP torsion 871225.33 Calpho w9nk 


4+n6tto 2R1> Hoc vl. 




1 ready at Sun Jul 16 12:01:03 1989 






user anonymous 






33 1 Enter PASS command 






pass Green 






230 Logged in 






dir 






200 Fori command okay 






150 Opening data connect ran for LIST n6ouu:pub: 






d Errf Hay3£ 02: 12 89 ttacF i les 






154608 0-rr Apr 13 09:54 89 nonox25.arc 






4990 0-rf Mar 31 02:30 89 HCPRMTG.SIT 






d 0-rf llay 12 18:38 89 PCFJies 






115238 0-rf Jun QB 01:53 89 rfclQxx.sit 






50352 0-rf Jwn 08 01:05 89 rfc793 sit 






U594 0-rf Jul 08 05-15 89 Short707,f+et 






d 0-rf Jul \b 18:46 89 Text Files 






Get complete, 424 bytes received 






226 File sent OK 
1 








a 


1 ^ 


XJ, 



Figure 2. An FTP session with a remote host. The user has logged on 10 the remote system and 
requested a listing of the files. 



£ File Edit Windows 



3:05 g 



Jxa£xi and 



You're bei*f 

net> 

Vou're betng 

net* finger S 

net> 

Vou're being 

net* finger 

net> 



route Command 



Fanciis/t: Displays /Changes the IP routing table 

S&ni&x: route [options] 

*pti*tts: < ed d > *hw t > *i rite r face > <« hos t > 
t(fropxl»at> 

AMrer.: ro 

Exmmpft: ro 

ro drop k3mc 

ro odd wa8dzp axO ko6r\en 



O 



t 



Topics 



ic^ 



BH\ 



Previous 



Cancel 






Vou're being fingered by 44,4. I 209: 1008 I <Sun Jul 16 14:29 09 1989) 
net> 



a 



Figure S. The Help screen for the ' 'route ' T command. 



started. Other sessions are created in the nor- 
mal manner from commands issued from the 
console session. The user can create a "Log** 
session which shows the contents of the sys- 
tem log from the time the program was stan- 
ed. The user can scroll the log to see what 
traffic the program has handled since it was 
staned. You can start a fc Trace" session for 
any active interface, The session window 
shows the trace output for the interface as 
specified by the user. 

Finger session windows are handled in a 
special manner. They are allowed to stay 
open after the session has closed. The user 
has access to the information displayed in the 
window until it is no longer required. In addi- 
tion, the "Finger/* "Log/' and "Trace" 
session windows are treated as read-only. No 
input is allowed to those sessions. 

You can resize all session windows and 
place them on the screen in any way you 
desire- You can observe the activity on sever- 



al sessions at the same time. This feature has 
proven very useful for normal program oper- 
ation . 

Figure I shows a typical screen with three 
windows, The top window shows the results 
of a cailsign query from a callbook server 
using the finger command. The middle win- 
dow shows a trace of all activity between the 
TNC and the computer, and the last window 
is the command console window, in this ex- 
ample the console is the active window. Just 
clicking on another window with the mouse 
makes a window active, 

MultiFinder. the pseudo-multitasking pro- 
gram for the Mac OS t runs Net/ Mac and 
BM/Mac at the same time. You can send and 
receive documents and mail while answering 
mail. The only requirement, of course, is lots 
of memory; 2,5 Megabytes suggested! Net/ 
BM and Net/Mac, running simultaneously on 
a Macintosh 5 12Ke, uses up too much memo- 

continued on p. 73 



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73 Amateur Radio * October, 1969 69 



Number 23 on your Feedback card 



Vertical Antennas at HF— Part II 

More surprising facts about HF verticals. 

byStanGibiliscoWlGV 



In Part I in the September 1 989 issue of 73 , 
the aspects of HF verticals I discuss arc 
polarization, ground wave propagation. 
grounding, use of radials, and calculating 
antenna efficiency. In Part II of this tutorial, 1 
discuss tuning coils and traps, useftil band- 
width, interference, and low-band DX con- 
siderations. 

Tuning Coils and Traps 

My purpose in discussing these is simply to 
offer suggestions for minimizing the losses 
they present. The importance of minimizing 
losses in coils and traps increases as the an- 
tenna is made shorter, since the radiation 
resistance decreases. A coil with 1 5£2of loss 
will not seriously degrade the operation of a 
vertical antenna 70 degrees high, but will 
devastate the performance of a vertical just 15 
degrees high. 

Use the heaviest gauge wire for coil wind- 
ing. Protect the electrical junctions from the 
elements and they should not, unless un- 
avoidable, be of dissimilar metals (for exam- 
ple, steel and copper). It's best to either weld 
or solder them. Minimize the total length of 
wire in the coil by using the smallest possible 
coil diameter and/or a low-loss powdered- 
iron core. Make sure the core is rated for the 
transmit power you want to put into the pow- 
dered-iron core, 

What's the difference between a coil and a 
trap? The major difference is that a coil serves 
only to physically shorten the length of an 
antenna without changing its electrical length. 
A trap also has this effect, but it also allows an 
antenna to operate on more than one band. 

In trap construction, the same general rules 
apply, with the additional constraint that the 
capacitors have low loss and be capable of 
withstanding the voltages that will appear 
across them. Traps should be resonant at the 
center of each band for which they are de- 
signed, or ideally, for the same frequency 
that represents the median operating frequen- 
cy in each band used. For example, if you 
prefer the lower CW parts of the 40 and 20 
meter bands, adjust the antenna and traps for 
about 7.025 and 14.025 MHz; otherwise set 
them for 7. 150 and 14. 1 75 MHz (the centers 
of the bands). 

Useful Bandwidth 

The useful bandwidth of any antenna is 
defined as that frequency range over which 
the SWR at the fcedpoint is at or below cer- 
tain limits. In practice, a good limit is 3:1 , or 
else that range over which the transmitter can 
be tuned for optimum operation without the 
need for an outboard matching network. 

70 73 Amateur Radio • October, 1989 



A full-size quaner-wave vertical antenna 
typically has a useful bandwidth of about 5 
percent of the resonant frequency. For exam- 
ple, if the resonant frequency is 14.200 MHz, 
then the useful bandwidth is around 700 
kHz— which extends beyond both ends of the 
band. This value will increase with increas- 
ing loss resistance, and will decrease as the 
antenna is shortened and inductively tuned. A 
properly operating short vertical might have 
a useftil bandwidth of only a few kilohertz 
when the ground plane (radial system) is suf* 
fie tent for high efficiency. In other words, 
you can still have an efficient antenna that is 
electrically short, but the trade-off is narrow 
bandwidth. 

The interesting (and possibly deceptive) 
point is that a lossy ground system often 
appears to enhance performance from the 
standpoint of bandwidth, as well as lowering 
the SWR if a matching transformer is not 
used. See the hypothetical case in Figure 8. 
The SWR-versus-frequency curves are for a 
33-foot vertical tuned for 3.800 MHz. The 




2 - 



4) 




3700 



seoo 

FREQUENCY, KH? 



3900 



4 - 



a. 



3 - 



2- 




37QO 



3BO0 
FffEOUENCY, KHi 



3900 



FigureS. (a) Typical resonant curve for short 
vertical with inductive tuning, low-loss 
ground, and matching transformer. At (h) 
The same antenna without the transformer 
and wish a lossy ground, Tftis graph gives 
the impression of good performance because 
of broad-handedness. Broad-bandedness 
doesn V always mean high efficiency! 



SWR at 100 kHz of either side of resonance, 

using no matching transformer and assuming 
a perfect ground system, would be about 
7.4: 1 (520/7Q), The bandw idth as previous- 
ly defined here would be zero unless a trans- 
former were inserted, and this is assumed in 
Figure 8a, 

As the loss resistance increases, the mini- 
mum SWR becomes lower, and the curve 
flattens out, giving the impression of broader 
bandwidth. If the loss resistance were to rise 
to 45Q— a quite real possibility with just two 
or three buried radials— the SWR would be 
flat at 3 , 800 M Hz , and the cu rve fairly broad , 
as in Figure 8b, without the matching trans- 
former. The unfortunate operator would 
suffer a severely deflated ego if he believed 
this were a good sign, as the instruments 
would appear to prove, and then was told* 
correctly , that : 

Eff {%) = 100(7/52) 
= 13 percent 

Obtaining Gain 

We have seen thai you can obtain omnidi- 
rectional gain with a half-wave vertical an* 
tenna w ith an extensive ground radial system. 
The ground plane doesn't increase antenna 
efficiency (although it may by a few percent, 
if the ground is very lossy), but it reflects ihe 
electromagnetic field, in effect creating a 2- 
element vertical collinear array. You can add 
more collinear elements and get more gain; 
doubling the number of in-phase elements 
increases the power gain by 3 dB. This is 
done at VHF and UHF. but seldom at HF 
because of the practical limitation on antenna 
height. 

Vertical elements may be phased to get 
gain in some directions at the expense of 
other directions. Two vertical antennas fed in 
phase and spaced x h wavelength apart pro- 
duce 3 dB gain perpendicular to the line con- 
necting both antenna feedpoints (Figure 9a) 
and zero signal along that line. If the antennas 
are fed in opposing phase, such as by adding 
x h wavelength of feed line into one of the 
antennas, this pattern is rotated 90 degrees 
with maximum signal along the line connect- 
ing both antenna feedpoints (Figure %), 

If both antennas are half- wave in height, 
and there is an extensive system of radials 
around each antenna, the gain will be 6 dB over 
a quarter- wave vertical alone, in the favored 
directions of the phased vertical system. 

Other phasing patterns are possible. One 
common feed system is to space two verticals 
■i wavelength apart and to feed them in phase 
quadrature (90 degrees out of phase). The 
result is a pattern with a null in one direction. 




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73 Amateur Radio * October, 1989 71 



This is called a cardioid partem since it is 
heart-shaped* There is some gain in the 
favored direction of this system, but the lobe 
is very broad, 

A Stcerahle Vertical Vagi 

Another way 10 obtain directivity and gain 
is to use one or more parasitic elements. The 
driven element may be a quarter-wave verti- 
cal antenna, and the parasitic elements about 
5 percent longer (for a reflector) or shorter 
{for a director) than the driven element. A 
2-clement vertical vagi may use cither a 
director or a reflector in conjunction with 
the driven clement. The parasitic elements 
are not connected to the feedline, but instead 
are short-circuited to their radial systems 
(Figure 10). 

You may move the paras itic elements by 
manually changing the positions of the 
elements, moving them in and out of pre-set 
holes or rods in the ground. This does not 
make for quick switching of the antenna's 
direction, but it may be useful if you don't 
need this feature. Alternatively, you may 
make the parasitic elements S percent shorter 
than the driven element, and lengthen them 
with small inductances in series , thus con- 
vening from director to reflector. 

Figure 1 1 shows a switchablc bi-direction- 
al system. The parasitic element acts as a 
reflector when the relay is open, 
and as a director when the relay is 
closed and the coil is short-circuit- 
ed. The parasitic element is physU 
cally 5 percent shorter than the 
driven element; with the coil in- 
serted, it is electrically 5 percent 
longer. The 2 elements are spaced 
0J5 wavelength apart. This dis- 
tances, is given by: 

S feet = l48/f MHz 
S meters = 45 M MHz 

This switchable array gives 
about 5 dB forward gain over a 
single quarter-wave vertical. 

You might put such an antenna to 
good use on 40 or 80 meters for 
contest work from the Midwest* 
for example. 

Adding the parasitic element 
lowers the impedance of the anten- 
na at resonance, which most likely 
causes an increase in SWR. You 
may use a matching section or 
transformer to lower SWR, if 
desired. You can construct a 
matching section from a % -wave 
section of 52D line (the velocity 
factor of the line must be taken 
into account) and the main feed- 
line from 75 Q coaxial cable. Most 
transmitters will work all right 
with 75D fecdlines having reason- 
ably low SWR. If a 75fiTfeedline 
is used, however, do not rely on a 
52Q SWR meter for accurate 
indication. 

The gain and directivity of this 
antenna will be evident for receiv- 
ing as well as transmitting. 



Verticals and Interference 

You often hear that a vertical antenna picks 
up more manmade interference, especially 
from appliances such as vacuum cleaners, 
hair dryers, and electric blankets, than a hori- 
zontal antenna. It is true that the vertical 
component of noise tends to propagate a little 



A) 




LINE CONNECTING 
ANTENNAS 



0) 




LINE 
CONNECTING 

ANTENNAS 



Figure 9. Verticals spaced at ¥i wavelength 
and fed in phase (a} and ISO D out of phase (h) 
p radii t r ih ese di recti ona I patte n ? 



REFLECTOR 



RADIAL 
SYSTEMS 



I 



K DRIVEN 

ELEMENT 



— DIRECTOR 



o 



uJ 



COAXIAL 
FEED 



Figure 10. Three-element vertical yagi. Vie driven element is l 4 
wave; the reflector and director are 5 percent longer and shorter, 
respectively. 





*- PARASITIC 

ELEMENT 


■•—DRIVEN 
ELEMENT 


RELAY 






SWITCHED ^ll 
POWER «* — J " 




. TUNING 
COIL 










RADIAL SYSTEM 


L- 


r 


COAXIAL FEEO 



Figure If. A switchable bi-directional vertical yagi. Tlw parasitic 
element is physically 5 percent shorter than the driven element, but 
opening the relay causes the coil io be inserted, lowering the 
parasitic frequency to that of a reflector. 



further than the horizontal component be- 
cause the latter is cancelled out by ground 
plane effects. Nonetheless, you can go a long 
way to reducing the noise simply by placing 
the vertical further away from the electrical 
wires and house. In practice, a vertical amen- 
na may be more likely to pick up interference 
than a horizontal antenna, simply because the 
vertical will usually be closer to the sources 
of interference. 

A ground-mounted, backyard vertical an- 
tenna is surrounded by houses with their un- 
shielded wiring, and the problem is com- 
pounded if utility wires are above ground. In 
this kind of situation it may be better to mount 
the antenna up Va wavelength and use three or 
four radials (for each band) that may double 
as guy wires. Alternatively, you could use a 
separate receiving antenna, such as a ferrite 
loopstick with a preamplifier. You can orient 
this type of antenna to null out the noise. 

Vertical antennas may cause more radio* 
frequency interference (RFI) than horizontal 
antennas for the same reason: the ground- 
mounted vertical will usually be closer to 
home entertainment equipment. Again, the 
solution is to get the antenna in the clear and 
well away from home wiring and appliances* 

Low-Band DX Considerations 

For long-distance communica- 
tion at frequencies of 7 MHz and 
below, the vertical antenna is a 
good choice when space is limited, 
A dipole antenna must be at least 
{ A wavelength above the ground to 
have good low-angle radiation: 
this will require two supports of 
that height. But a l i-wave vertical 
radiator w ith a good ground radial 
system will provide just as much 
power gain as the dipole, will radi- 
ate well at the low angles desirable 
for DX. and will do it in all direc- 
tions—with just one support of 
half the height, 

A ^-wavelength vertical with- 
out radials will equal the perfor- 
mance of the { A -wave vertical with 
radials: adding the radials to the 
taller antenna will provide 3 dB of 
power gain at low angles in all 
directions. Verticals may be 
phased or combined to form para- 
silic arrays with directivity and ad- 
ditional gain. 

Probably the most visible ad- 
vantage of a vertical antenna is its 
unobtrusiveness. Even a quite tall 
vertical is not an eyesore to most 
onlookers. You must take care to 
ensure that the antenna cannot 
come into contact with utility 
wires, and some local ordinances 
forbid manmade structures that 
will not fall entirely within the 
owner's property. But for the cost, 
effort, and space, the vertical an- 
tenna may be the best choice for 
the ham or SWL seriously inter- 
ested in low-band DX 



12 73 Amateur Radio ■ October, 1 999 



continued from p. oV 

ry to run MuIriFinder on that system. Wc 
recommend at least a Macintosh Plus, 

FTP and MacBinary II Support 

FTP (File Transport Protocol) provides a 
method of reliable transfer of files between 
machines on a network. You can use it to 
transfer both ASCII and binary files. To 
make it easier to transfer Files between Mac- 
intosh systems running NET/Mac # we added 
the MacBinary II file transfer protocol to the 
program. Along with the normal data in a 
file, this program sends all of the Macintosh 
specific file information (e.g. program 
specific icons for the desktop). This is neces- 
sary as the Macintosh file system is quite 
different than that of other systems and re- 
quires additional information not transferred 
in an "image" mode FTP transfer. 

Figure 2 shows an FTP session with a re- 
mote host. In the example, the user logged on 
to the remote system and requested a listing 
of available files. 

Online Help 

Another useful addition is the online Help 
Facility to both NET/Mac and BM/mac. To 
call it up f just select Help from the "Apple* 
menu, The help system documents all the 
available commands in each program. Figure 
3 is an example of the Help screen for the 
"route*" command. 

\ppk-Talk Support 

We added a driver for AppleTalk , the local 
area networking protocol built in to every 
Macintosh. Here's an example of how we 
were able to make use of this support, At my 
QTH, I have a Macintosh Plus connected to a 
Yaesu FT-21 1 via an AEA PK-232, Howev- 
er, I do most of this work on a Macintosh II 
located across the room, Since AppleTalk is a 
networking protocol, all I have to do was 
connect the two computers together with a 
cable* and voila!: My Mac n now sends and 
receives files and maiL with no additional 
radio or TNC . AppleTalk allows me to assign 
another IP address to my Mac II , and send/re- 
ceive files and mail via the Mac Plus. In fact, 
any number of Macintosh's can be connected 
(up to the limit of254!) toasingle radio/TNC 
via the AppleTalk network. With additional 
hardware, I could even connect io the main- 
frame computer via a telephone line. No ad- 
ditional software is needed. 

Operation With Other Packet Systems 

The package also interoperates with regu- 
lar packet services and telephone networks, It 

supports normal AX. 25 connect mode for 
key board-to- keyboard * 'chats 1 and PBBS 
sessions. A mailbox facility is also available 
similar to other personal mailbox systems in 
TNCs. It also handles NET/ROM for chat 
sessions or as a transport mechanism for 
sending TCP/IP packets through exisiting 
modes. 

Summary 

Bringing the KA9Q Internet package to the 



Macintosh was very rewarding? We will con- 
tinue improving the user interface to give the 
packet community an eajsv to use, "appli- 
ance-like" version of TCP/IP. 

The code is public-domain and is available 
from Doug N60YU for $5 for the disk, 
which includes postage and handling. You 
can also download the code from various 
locations on the Internet. Doug's Internet ad- 
dress is thomapplc .com. 

Wc hope our efforts will stimulate more 
interest in this intriguing new dimension in 
packet radio! 



Doug Tttom N60YU has been at Apple Com- 
puter since 1979, and currently serves as a 
costumer support engineer there. Doug has 
been active in amateur radio, especially in 
the digital modes, for four years. Other inter- 
ests include car racing and scuba diving. He 
can be reached at 1405 Gray wood Drive, San 
Jose CA 95129-4778. 

Dewayne WAHDZP has been licensed since 
1961 1 and is involved solely in packet. He is a 
free-lance software consultant. Dewayne al- 
so enjoys flying his own plane and scuba 
dhing. 



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Continued from page 8 

more, Okay t let me repeat a bit of 
another recent editorial, backed 
up by the Connections program I 
saw on PBS. You have to be terri- 
bly out of touch not to know thai 
atomic bombs are now portable 
enough to fit in a suitcase — per 
the illustration on Connections, 
So all that's necessary is for one 
terrorist group to grab enough nu- 
clear material, and guess where 
they're going to head, suitcase in 
hand? 

Nuclear material comes from 
atomic power plants, where sever* 
a I recent reports have shown se- 
curity often is pitiful. Plus we have 
nuclear sources now in more and 
more Third World countries, How 
much trouble would Kaddafi have 
getting enough for a bomb? The 
French seem eager to sell atomic 
energy equipment to virtually any 
country interested. 

So it's more a question of when 
we're going to be faced with a nu- 
clear terrorist than it As I asked in 
an editorial— how ready is your 
club? If you're around New York 
or Washington, you'd better be 
very ready, with as hardened pro- 
tection against EMP as possible, 
with as high-speed automated 
communications as the state of 
the art will allow Depending on 
Morse Code for communications, 
where we'll be the only service ca- 
pable of replacing the telephone, 
is about as effective as planning to 
use smoke signals. 

Not only are the military almost 
totally dependent upon tele- 
phones, so are virtually all other 
disaster groups. Civilian Defense 
officials have almost universally 
given up even trying to use ama- 
teur radio links— too siow t com- 
pared to picking up the telephone. 
Ham communications is slow, se- 
riously prone to errors, and too 
dependent upon older men with- 
out the necessary stamina. 

Now, lest I be put down (now, 
who would do that?) for doom and 
gloom without solutions, the way 
to resolve this is to first get the 
FCC to hefp us find out how to 
cope with EMP, despite the unrea- 
sonable resistance of the DOD. 
Second, it's time to recognize our 
need for a million or so active 
hams, instead of more like the 
150*000 we seem to have today. 
Third, we need to urge the few 
technically competent hams we 
have — those who didn't Bash or 
bribe their way to Extra Class — to 
start working on high speed auto- 
matic digital communications sys- 
tems — like packet, only much 
faster. We need to be able to 
provide million-message through- 
puts, not dozens, and our gear 
should be capable of being oper- 
ated by anyone around who is still 
alive. 

We have the technology to do 
all this, all we lack is the techni- 
cians and the guts to face the 
biggest challenge of our lives. 



Lacking this, my suggestion is to 
move as far away from New York 
or Washington as you can — and 
soon! Living near those death 
traps could be more harmful than 
smoking, or even Southern Cali- 
fornia and its coming humdinger 
earthquake. 

The Emperor's Clothes 

A few years ago I caused a terri- 
ble uproar by proposing that if the 
code really was as important as 
was being claimed, then why not 
have alt of us prove every so often 
thai we know the code? Since I 
knew from surveys that over half 
of all licensees would fail even the 
simplest of code tests , 1 wasn't se- 
rious. 

Back in 1960, when t started 73 
Magazine, thousands of new 
hams were coming into the hobby 
via friends who "gave 1 them 
Technician licenses. It was esti- 
mated at the time that roughly 
75% ot all new Techs had no 
knowledge whatever of the code 
and only the vaguest interest in 
theory. 

The editor of CO in late I960 
gave Tech licenses to virtually the 
entire CQ staff, none of whom had 
the slightest technical back- 
ground or any knowledge of the 
code, Later he set up a dummy 
address in Maine and gave them 
General licenses, still with no 
tests of any kind. Unfortunately, 
this activity wasn't unusual for the 
period. 

A few years later, when CB was 
going strong and more people 
started getting interested in ham 
tickets, Dick Bash showed up with 
a new way around the ham ex- 
ams. Now t in a weekend of short- 
term memorization, one could be 
virtually guaranteed a ticket- Dick 
would sell you exact copies of the 
FCC code and written exams and 
then coach you in how to pass 
without actually knowing any- 
thing. I personally know many Ex- 
tra Class hams who couldn't pass 
a General Class code test if their 
lives depended on it. They 
Bashed their way to Extra, Some 
of these are particularly sanctimo- 
nious about the code today. 

Once the FCC spoiled Bash's 
game with their VEC tests, the ball 
was in another court. Now I have 
no doubt that there are many hon- 
est VECs, but I know from my mail 
and talking with hams at hamfests 
lhat there are VECs who view this 
position more as one of opportuni- 
ty than of service. The FCC is still 
trying to sort out how many thou- 
sand Extra Class licenses were 
sold by Puerto Rican VECs. I've 
recently heard of large scale li- 
censes-for-cash deals in New 
York, New Jersey, California, Col- 
orado and a few other areas. 

Yet, despite what appears to be 
the widespread buying of ham li- 
censes with no code or written 
tests, we still have virtually no 



ham growth— O.Q% for the last 
year. 

When you put things in that per- 
spective, it isn't particularly sur- 
prising that a high percentage of 
today's hams would go into com- 
plete panic at the slightest sug- 
gestion of a re-exami nation by the 
FCC. And that's what I ran into 
when i made the suggestion, even 
in jest. They had the tar heating up 
for me in case I attended any ham- 
fests. 

When the ARRL proposed to 
the FCC in 1963 that 90% of the 
hams be re-examined in order to 
maintain their voice privileges on 
the HF bands, the mere proposal 
of re-examination stopped ama- 
teur growth instantly. It so terror- 
ized tens of thousands of hams 
that they sold their ham stations at 
lire-sale prices. This f in turn, put 
95% of the ham manufacturers 
and 85% of the dealers out of 
business within two years. 

Incentive Licensing, as the pro- 
posal amusingly was cal led, was a 
killer. It was an incentive of 
sorts— either you get re-examined 
by the FCC or you get off the air on 
voice. That's an incentive, right? 
Well, it was to the thousands of 
hams who didn't know the code 
and believed they'd never be able 
to learn it. 

Sure, a few hams who were 
given their tickets by friends have 
taken the time to learn the code 
and even some theory. One of my 
73 editors told me how a friend 
had forced a ham license on him 
several years before. Eventually 
he got interested in repeaters and 
this encouraged him to start learn- 
ing theory. He never did learn the 
code, though he wrote and edited 
many ham technical books, 

So here we are today, arguing 
about a no-code license, some- 
thing we've always had. We're 
talking about offering the no- 
coders our UHF bands- We man- 
age to forget that Canada has had 
just such a license available for 
several years, and so far only 
about 100 Canadians have both- 
ered to go for it, Sure, let* s go the 
ARRLs proposed route, reinvent 
an unwanted license, and bet the 
farm on it. 

If you take a look at the Calf book 
list of licenses you'll find that 
about 42% are Novice and Tech- 
nician, and that's no-code. You 
don't even have to know all of the 
Morse characters to pass the 5 
wpm test, as we showed clearly in 
a 73 article. Of the 56% with Gen- 
eral or higher licenses, what per- 
centage would you say actually 
passed valid ham exams? By the 
time we rule out gifts from friends, 
the Bashers and VEC cash licens- 
es, what have we left? Well, we 
have the shambles our bands are 
in today. And we have a wide- 
spread lack of technical knowl- 
edge. We also have almost com- 
pletely lost our ability as a group to 



design or butld innovative equip- 
ment. Tm having to turn to Japan, 
Australia, England and Germany 
to get simple construction project 
articles for 73. 

Could 20% of today's US ama- 
teurs pass a 13 wpm code test? 
How much would you bet on it? 
Should we come to grips with this 
reaJity and go back to the '50s sys- 
tem where perhaps half of all new 
hams were fraudulently given 
their licenses? Should we go back 
to the last period of ham growth 
and put Dick Bash back in busi- 
ness selling the word-for-word 
ham exams and running weekend 
crash classes? Or should we sell 
VEC licenses and let them recoup 
the cost by selling ham exams? 
The first two systems worked 
best, the VEC sales haven't man- 
aged to provide any significant 
growth. No, the old license-your- 
wife, license-your-friends system 
brought us the most growth. The 
problem with that system was that 
it stopped with the Tech license, 
resulting in almost half the li- 
censees never getting any further, 
even after 30 years. 

What abou! the golden old days 
of amateur radio, was it better 
then? As far as the code was con- 
cerned, yes. In the T 30s you actu- 
ally had to be able to copy the 
code at 13*per to get a ham li- 
cense- The theory? Well, no. 
There we had the ARRL License 
Manual, an almost word-for-word 
key to the FCC exams, A high per- 
centage of the hams of yesteryear 
memorized their way to their tick- 
ets. Alas, memorization like that 
lasts for only a few days and is 
gone— forever. Any college stu- 
dent will verify that for you, in case 
youVe managed to forget that fact 
of life. 

To look at the long term, we've 
always had a tiny handful of doers 
and a large contingent of watch- 
ers- As a ham publisher over the 
last 40 years, I've had the privi- 
lege of knowing most of the doers 
personally. When I was a kid on 
roller skates in Brooklyn in the 
'30s I visited every active ham I 
heard on the air. There weren't 
many hams then, so it wasn't all 
thai difficult, i found that hardly 
any of them had more than a 
vague understanding of radio the* 
on/, even as simple as it was in 
those days. I found one ham had 
built his own receiver, and he was 
looked upon as a technical wizard 
by the others, 

I did the same as everyone 
else — I memorized the theory and 
got my ticket. But it wasn't until I 
went through the Navy technical 
schools in 1943 that I actually be- 
gan to understand the basics of 
electricity. 

I've tried asking some fairly sim- 
ple technical questions during my 
talks at ham conventions to see 
how many in the audience under- 
stand them. I'd estimate maybe 



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2% of the hams understand 
enough theory to get up and try to 
teach even a Novice class. 

When we were handing out 
ham tickets on street corners, so 
to speak, we had 11% annual 
growth and we found that we were 
attracting youngsters. 80% of the 
newcomers were youngsters. We 
also found that tor some reason 
the hamming experience influ- 
enced their lives, since 80% of 
them went on to high-tech ca- 
reers. 

The Bash system, since it cost 
money, knocked out most of the 
kids and brought us older hams, 
but only about 10% as many as 
we were getting by giving away 
licenses. The VEC tickets-for- 
cash put licenses out of the range 
for most kids, further driving up 
the average ham age. 

Well, what do you think we 
ought to do next? Shall we go the 
ARRL route and relive the Canadi- 
an fiasco? Shall we go back to the 
*30s system and make everyone 
actually pass a code test? The 
code was more important then, 
since 90% of all ham activity was 
on CW. Phone rigs were just too 
ex-pensive for most hams. 

One of the first ham phone 
transmitters put on the market 
(around 1939) was the National 
600. It sold new for about S25 t 000 
in today's dollarettes. The flood of 
war surplus drove ham equipment 
prices down in the late '40s, so I 
was able to buy a used "600 1 ' in 
1 947 for a fifth of the original price, 
one of my better ham investments, 

Considering the above per- 
spectives, please let me know if 
you have any proposals which 
might tend to get amateur radio 
Some growth. 

Those Pesky Minorities 

Amateur radio in America, for 
all its facade of internationalism 
and pretense of being a world f ra- 
lernity, has been primarily a 
closed White community. Oh T it's 
been open to women, but not on 
an equal basis. And it's never 
been congenial for Blacks or His* 
panics. It's almost getting time to 
start thinking about what this 
means to the future of amateur 
radio, and even to America. 

As one of the few hobbies capa- 
ble of interesting youngsters 
in high tech careers, amateur 
radio has a responsibility lo 
our country— to the world, actual- 
ly. The projections are that 
by 2000, one-third of our college 
students will be Black and Hispan- 
ic, Are we going to make sure thai 
few of these kids go into technical 
colleges by continuing to freeze 
them out of amateur radio? 
The end result will be even fewer 
American engineers, technicians 
and scientists. And that means 
a guaranteed lower national 
income as technology blos- 
soms in Asia and Europe, leaving 



us further and further behind, 

I mentioned in a recent editorial 
how few minorities we have in our 
hobby, I rarely see a Black at a 
hamfest. Some of our Puerto Ri- 
can hams come to Oaylon. but 
that's about it. How many Hispan- 
ic hams do you see at the big Dal- 
las hamfest every year? How 
many at Miami? 

If America was able to keep up 
with the rest of the world in tech- 
nology while keeping women and 
minorities out of amateur radio, 
we could just excuse whal we're 
doing as another manifestation of 
good old American red-neckism, 
We're a bunch of good or boys 
and we're going to keep out the 
riff-raff. 

Women belong rn the ham club 
auxiliary. We need 'em to bring 
the coffee and doughnuts. 
They're too dumb to be able to 
understand a technical talk, right? 
Well, that's what 1 see as an al- 
most universal American ham atti- 
tude, And, unfortunately, women 
seem to go along with this without 
a whimper. 

Oh. there are a few belligerent 
women who attack every imag- 
ined slight to women, usually do- 
ing more harm than good. Wom- 
en's Libbers has gotten to be an 
epithet. Being nasty as a way of 
breaking stereotypes doesn't help 
much. What we need are more 
shining examples. 

I know there are some fantastic 
women in amateur radio. Every 
now and then I meet one at a ham- 
fest or a club meeting where Tm 
talking. Some clubs are even 
proud to have such a woman. But 
let me ask you this, when's the 
last time you read an article in a 
ham magazine about a woman 
ham who has accomplished any- 
thing significant? Come on, felias, 
let's put some light in the dark- 
ness—let's see some promotion 
of your good examples. And that 
holds for women and all of our mi- 
norities. 

Martin Jue (MFJ) visited us with 
his chief engineer. Steve. Steve 
Pau KF5C is an Extra Class ham 
and comes from Malaysia— Sa- 
bah, to be exact. Sabah 9M6 is a 
beautiful country, one you should 
make an effort to visit. You aren't 
going to find a more friendly coun- 
try, We've had quite an influx of 
Asians in recent years, You've 
read about how their children are 
running circles around American 
children in school, mainly be- 
cause their parents have been 
pushing them to be well educated , 
while ours have been busy watch- 
ing Lucy reruns, Johnny and 
Oprah. 

Over half of the American col- 
lege graduates today are foreign 
students, and thai holds for our 
technical colleges, too. This 
wouldn't be so bad if this meant 
we had to build more colleges, but 
the problem is that our colleges 



are failing right and left. Several 
have failed around my area just in 
the last year! So we have fewer 
and fewer colleges and more and 
more foreign students in the ones 
we have. It's almost enough to 
make a person think. Even a ham. 
Could we be doing something 
wrong? 

A recent letter from an old ham 
friend was critical of the League 
for not having any minorities on rts 
board of directors. No Blacks. No 
Hispanics. And only one woman! 
Tsk. No, I'm not going to trash the 
League because they so accu- 
rately represent our hobby in this 
respect— represent the actuality, 
not the utopia. 

Heck, until fairly recently it was 
impossible for a Jew to get on the 
board. I remember when the first 
Jew was elected and was referred 
to as a Hymie by the other board 
members. That was only about 
twenty years ago. Now there are 
four Jewish directors. 

Okay, I've laid out a problem for 
you. We're doing amateur radio 
and our country a disservice by 
excluding minorities. What can 
we do to change this? Sure. I 
could tell you what I think, but it's 
time for you to do some thinking, 
some problem solving. You tell 
me. Write to me, Fa* me. Send me 
ARRL messages. What do you 
propose? 

One way to solve a problem is to 
look for some place in the world 
where that same problem, or a 
similar one, has been solved suc- 
cessfully. This has been my ap- 
proach to coming up with solu- 
tions to such miseries as welfare. I 
looked for a parallel situation 
where a group of people were des- 
perately poor and needed to start 
a whole new life. I found a fine 
example of this In another coun- 
try, an example which I think could 
be transplanted to America quite 
successfully and break the whole 
welfare system apart. The money 
we T d save just by solving this 
mess would largely cure the 
deficit — at least until Congress 
could cook up some other ways to 
spend the saved money. 

So — what do you suggest? Do 
you know of any ham clubs who 
have welcomed Blacks or Hispan- 
ics? I don't remember seeing any 
pictures of such a club crossing 
my desk— despite my repeated 
requests for same. Lacking any 
communications to the contrary, 
it's easy to assume that few, if 
any . ham clubs are even modestly 
integrated. 

With more and more Americans 
being minorities, we're painting 
our hobby into a smaller and 
smaller corner by ruling these 
groups out as candidates, Tell me 
again how you don't agree with 
me 100% — and then tell me why. 

Still More Grousing 

We're in a technological age. 



and that means communications, 
and that means frequencies. Not 
only are we well into a techno- 
logical age, it's only going to get 
more high tech, Just look at the 
changes in the last few years- 
telephones so complicated we 
have to be retrained to use them 
after every coffee break, Fax in 
almost every office, spewing out 
letters and reports all day long. 
We have to cope with computer 
bulletin boards, data networks like 
CompuServe, police radar and 
cellular radio. 

Satellite dishes in back of a 
million homes. Cable TV bringing 
in 100 channels of garbage- 
garbage which the average 
youngster ts watching Sto hours a 
day, by the way. The average fam- 
ily is watching 1 1 V? hours a day I Is 
it any wonder so few know how to 
read, are able to find the US on a 
map, or know who won the Civil 
War? Or that only 7% of high 
school graduates can even hope 
to be able to cope with a technical 
college? 

Parents, with the TV on all day, 
no longer have an opportunity to 
talk with their kids, so they get 
almost zero of what we used to 
call family education. Kids aren't 
encouraged and helped in their 
school work by parents, other 
than Asian immigrant parents. 
They aren't being taught values, 
goals, how to cope with growing 
up, how to cope with drugs such 
as alcohol, nicotine, pot, uppers, 
downers and so on. 

Is it any wonder in this age of 
kids left to drift— kids who are be- 
ing graduated from high school 
with so little education that many 
can't read— that something as 
complex as amateur radio, a tech- 
nical hobby, seems an impossible 
goat? 

As I see it t we have a choice; we 
can maintain our high stan- 
dards. . .and lose amateur radio, 
or we can try to change the coun- 
try, to educate parents and get 
them to turn off their TV sets for a 
few hours a week. Like any other 
bad habit, not talking with one's 
kids comes about as a result. No 
one means to neglect their kids, 
but it's just easier right now to 
watch the Today Show, the 
evening news. Tonight, So we put 
off talking with the kids until to- 
morrow, and tomorrow. This, 
faster than you think, turns into 
years and one day you notice 
you've got a big problem. By then 
it's too late to establish a rapport, 
so you're stuck with the mess 
you've made of your kid's life. 

Some parents almost wake up 
to what's happened when they go 
to their kid's funeral — drunk driv- 
ing, or another crack death. Oth- 
ers are more fortunate and only 
have a teenage pregnancy prob- 
lem* which quickly converts them 
to the pro-choice religion. The ob- 
vious response is to get mad at the 



76 73 Amateur Radio * October, 1989 




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73 Amateur Radio » October, 1989 77 



kids, not ourselves. After all. we 
meant well, If s just that we were 
too busy. 

Your kids into heavy metal? 
Probably, unless you've spent 
some time introducing them to 
classical music. We're into the 
largest move into classical music 
in history, courtesy of the compact 
disc, Millions of people in their 30s 
who used to buy rock LPs are now 
buying classical CDs, Indeed, I've 
published a guide to classical mu- 
sic which has been immensely 
popular. That's all fine for getting 
kids interested in better music, 
but it still doesn't give parents any 
more time to talk with their kids. 
And that means our job of attract- 
ing youngsters to amateur radio 
isn't any easier. 

If we're going to have a prayer 
of holding frequencies, we've got 
to use them, and that means we 
need more hams. The reason we 
haven't used 220 is thai we 
haven't really needed it for any- 
thing. 2m has more than enough 
room in 99% of the country- 
room to spare— and if we didn't 
have a tacit agreement that every 
ham has a right to his own re- 
peater channel, we'd have no 
problem even in Southern Califor- 
nia. 95% of the repeaters there 
are unused 95% of the time— just 
like everywhere else, A small 
group of repeaters handle most of 
the action. 

450 in So. Cal is "full' —why? 
Private, protected frequencies 
for every repeater fink, repeat- 
er and remote base, that's why. 
The actual use is pitiful Virtually 
every link on 450 could be moved 
to 10 GHz and all put on one 
freq with directional dish anten- 
nas, and with no interference. 
Instead we have repeater wars 
and mounting legal battles over 
who has the right to coordinate 
these almost totally wasted chan- 
nels. Quick, graduate more 
lawyers, 

We have 500 MHz going 100% 
to waste on 10 GHz. Some 
99.96% of our total frequency al- 
locations are totally unused. If you 
were an FCC commissioner, what 
would be your reaction to this? 
Here we have what is obviously a 
dying hobby, something used 
99.99% to entertain a dwindling 
group of crotchety old men who 
are using about 004% of a des- 
perately needed national re- 
source, 

WeVe got high definition TV, 
improved mobile and persona! 
communications— probably via 
satellites in the wings — as fast as 
the Japanese can perfect the new 
systems for us. 

Yes, there was a time when 
the hobby was needed as a re- 
source for the country. It was a 
way to get youngsters interested 
in electronics so they would self- 
educate themselves and thus be 
of value in case of war. Today few 



hams go beyond memorizing the 
expected questions and writing 
down the answers. The rest just 
pay off a VEC and walk away 
clean. The military woufd have to 
start from zero to train 99% of to- 
day's young hams— either of 
them. 

When we went into WWII we 
had about 50,000 licensed 
amateurs. 80% of those, 40.000. 
went into the military and were of 
enormous value. I joined the Navy 
and found my teachers in the 
Navy electronics schools were, al- 
most without exception, hams. 
The schools, by the way, were 
superb. 

WWII was largely won by our 
development of radar If was 
certainly shortened enormously. 
I know because I was there using 
It. I was able to guide my sub- 
marine, The USS Drum. SS-228, 
right through the middle 
of Japanese troop convoys on 
the surface in the middle of 
the night keeping track of every 
troop ship for aiming our torpe- 
does and every escort for avoid- 
ance They hadn't a clue just 
where we were as we sunk ships 
right and left, 

One could make a very good 
case that our amateurs contribut- 
ed most significantly to the win- 
ning of thai war. 

That's in the past, 1 doubt if one 
ham youngster in a hundred 
(if there are a hundred) would 
be of much value to today's 
military, Amateur radio is so far 
behind both military and commer- 
cial communications and elec- 
tronics that hams today would 
have to start from zero. We're still 
sending messages by hand key at 
around 10 wpm while the world is 
zipping along at 56K — and speed- 
ing up. 

The tech age is here — commer- 
cially. We hams are still radio 
relaying with hand keys, send- 
ing hey, how are you messages 
by the hundreds. I got a nice 
birthday message via the Re- 
lay League traffic network, sent 
two days before my birthday 
and delivered ten days after; 
came from Connecticut. Great 
message handling system for 
1989. eh? 

In the meanwhile the Japanese 
are working on voice compres- 
sion systems which digitally com- 
press the voice down to an effec- 
tive five hertz bandwidth. The Rl- 
AA fuss over DAT tape may have 
reached your consciousness. A 
DAT tape will hold two hours of 
extraordinary hi-fi digital sound. If 
we digitize the phonemes, we can 
store 18 months of voice on the 
same tape. Do we have the poten- 
tial for setting up voice channels 
every 10 Hz on 20m— that's 
100 per kHz— 35,000 channels? 
We have about 150,000 ac- 
tive hams, so that's about five 
per channel. We can live 



with crowding like that. 

Is it time yet to speed up our 
packet system from the present 
casual 1 .2K to 56K? This is pretty 
standard for commercial work- 
that 's about three thousand words 
per second. If you can read 
300 words per minute, you'd 
be able to keep up with your read- 
ing ability by sending 1/10 second 
messages every minute. This 
would allow up to 600 QSOs 
on every channel. Of course, 
we can only type at around 30 
words per minute , so we'd be bad- 
ly input bound. We'd type for ten 
minutes, s^nd it in 1/1 0th sec- 
ond — read it for a minute — and so 
on. Ho hum. 

Perhaps, like SSTv\ well start 
putting our stuff on disk or tape 
and sending previously written 
(archive) material, That'll make us 
work more like a newspaper, 
spending most of our time writing 
things to send. 1 ran into this prob- 
lem with RTTY back in 1 948. forty 
years ago. We used punched tape 
then, but we found we had to 
paste together rolls of it and feed it 
through the reader to keep up with 
our printers. 60 words per minute 
calls for very fast typing, but is 
slow reading. So I'd keep rolls of 
tape with punched stuff I'd previ- 
ously written at hand and feed it 
into my tape reader while I was 
punching my answers to the last 
transmission, When my prepared 
tapes were sent, I'd rip off my new 
tape and feed it through, It was 
hectic, but fun. 

Unfortunately, after a couple of 
contacts with someone to whom 
I'd sent all my material — now 
what? If a exasperating to sit there 
and watch your page while a hunt 
and peck typist finds each letter 
on his keyboard and sends it at 
more like ten words per minute 
than 60 You sure can get all over 
your RTTY enthusiasm fast after a 
few of these turkeys. 

The RTTY data burnout prob- 
lem is very similar to that with 
SSTV. Watching the same old 
slides over and over from the chap 
you've contacted is a killer Hey. 
I've already seen your shack, your 
XYL and the harmonics. Yes. I've 
seen your dog. Now what? 73» 
right? 

Well, if I ever get the time to 
get on RTTY, f m loaded now, I've 
got around 70 computer disks 
packed with materials I've written. 
Heh. heh! With only a little editing, 
I can take my articles* editorials 
and letters and have them ready 
to keep someone reading for a 
week after a five minute contact. 
Weil, I could if we'd get our 
speeds up. At 1200 baud I'd be 
sending for a week. Heck, it's all 
automatic, so why not? No. Td 
never gat any second contacts 
with anyone, but the first would 
sure be a zinger! L could run 
through a whole box of paper for 
them, Get your hard disks ready, 



I've got about 30 MB ready to 
dump on you. 

Which brings me back to our 
need to get amateur radio grow- 
ing—with kids. We need it to keep 
from losing our hobby. America 
needs it to keep from losing even 
more technology to Japan, Our 
kids need it if they're going to be 
able to cope with the world of 
2000. We're talking technology at 
every turn— communications, nu- 
merical control of machinery, au- 
tomation and robots, computers 
on almost every desk in offices 
and doing the nitty gritty work for 
most businesses. 

If we're going to attract kids 
we've got to come to grips with 
the fact that what we're doing 
now has failed— totally. We're 
down about 54% in newcomers 
into amateur radio in the last four 
years, rapidly heading toward ex- 
tinction. 

Yes, if we could gel parents to 
get their heads out of the family 
TV set and start giving their kids 
some help, some encourage- 
ment, get them excited about 
learning instead of being saturat- 
ed with TV, heavy metal rock and 
the almost inevitable (now) experi- 
mentation with increasingly lethal 
drugs, so what else is there to do? 
We might be able to con today's 
kids into learning the code the way 
we had to fifty years ago— before 
TV. Until you figure some way to 
retrain parents, we either have to 
change our ideas and come to 
grips with the real world, or we're 
out of here, 

I do have some hopes of bring- 
ing about a major change in our 
educational system, with an eight- 
year course in the fundamentals 
of electronics, one which goes to 
lengths to get kids interested in 
hamming. But that's not going to 
happen next week. 

Incentive licensing destroyed 
the whole infrastructure of school 
radio clubs which brought us 80% 
of our hams, The sooner you can 
gel your local schools to work with 
your ham club to get new radio 
clubs started, the sooner well 
start at least having a chance at 
rebuilding our hobby. In the mean- 
while, either we find a way to sell 
the product or we're out of bus- 
iness. 

Oops, There Goes Six! 

It's beginning to took like a feed- 
ing frenzy as commercial inter- 
ests, their juices up over the 
ease wrth which the FCC topped 
off 40% of our 220 band for 
UPS, are going after more ham 
bands. 

There's an announcement in 
Broadcasting magazine (tnx 
WA4ZID) that Lawrence Tighe 
K2JIA t who owns WRNJ in Hack- 
etlstown. New Jersey, has pro- 
posed that the 50-54 MH2 ham 
band be made a new FM broad- 
cast band. Thanks, Larry, 



78 73 Amateur Radio * October, 1 989 



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isn't surprising, as the setting is critical; for 
HF packet you have to tune to within 10-20 
Hz of the center frequency. 

Use Your Ears 

An off- frequency station on an HF packet 
channel sounds distinctly different from 
properly-tuned stations. With this in mind, I 
developed a packet signal synthesizer that 
contains the proper frequency components to 
use as a tuning aid. 

This project began with this general idea, 
and the resulting device is very effective. 
Tuning is a snap, and you can optimize it 
within the needed Hertz. The circuit is sim- 
ple, and you can buy every part, even the 
p re-drilled /solder-ring circuit board, at Ra- 
dio Shack. 

How It Works 

Refer to the block diagram in Figure 1, 
A square- wave timer provides the space 
lone (typically 2.310 Hz), and a diode 
switch makes the necessary 200 Hz frequen- 
cy shift keying for the mark tone. A second 
square-wave timer keys the switch at 35 Hz 
to simulate packet keying . This is followed 
by an active filter with a response centered 
between the space and mark frequencies. 
The filtered output combines with the radio 



output for the audible comparison. The 
assembly includes controls to adjust the 
radio output amplitude and the level of the 

synthesized packet signal to the phones or 
speaker. 

For CW applications, the 35 Hz tone 
switches off to leave only the space frequen- 
cy , which is also the PK-64 Morse filter fre- 
quency. Zen>bcating the radio C W signal to 
the filler frequency gives you much improved 
automatic Morse decoding. 

Circuit Details 

See the schematic in Figure 2 . One section 

of a 556 1C dual timer makes the space/mark 
square wave. CI, Rl, and R2 make up the 
related space frequency time constant, with 
R2, the lOkfl potentiometer, providing fre- 
quency trim. Rl is the value used to get 2,3 10 
Hz, the HFM-64 space frequency. You can 
change this resistor for other space frequen- 
cies. For example, add 1 0k for 1 .800 Hz. 

Switching in C2 makes the lower mark 
frequency, the series 50kD R3 potentiometer 




Photo A. Component layout on the HF packet 
tuning aid board. 

changing the reactance enough for the fine 
trim. The C2 value is for the HFM-64 2 J 10 
Hz mark tone, Change C2 for other mark 
frequencies. For example, add another 470 
pF capacitor tor I.6O0 Hz (assuming 1,800 
Hz space tone). Two 1N914 diodes switch 
C2. Biased off for the space tone, they are 
switched on for the mark tone by switching 
transistor Q 1 . 

The 556 IC second section makes the 
square wave used to switch between the space 
and mark tones, the l-MQ time consiant po- 
tentiometer R4 providing a range of a few 
cycles to several hundred. Experimentally 
selected, the 35 Hz keying rate sounded most 
like the nominal packet signal. The PK-64 



UOftSE S* 

1-0- 



SQUARE WAVE 05C 



HARK 
SW 



SQUARE WIVE OSC. 
SPACE /MARK 

12 310/2 noma 



FILTER 

I2?10hii 



AUDIO 
AMP 



-X* 



PNOHES/ 
SPEAKER 



* RAQtO 
"^ INPUT 



Fig. L Block diagram of the HF packet tuning aid. 




IZWBSmA 






PHONES/ 

SPEAKER 



s RADIO 
^ INPUT 



Fig. 2. Schematic diagram of the HF packet tuning aid. 



80 73 Amateur Radio • October, 1989 



Morse function is accomplished with a me- 
chanical switch thai disables the modulation, 
leaving only the space tone. 

A lypicaJ active op-amp filters the timer 
square-wave output, and R5 allows you to 
adjust the peak response frequency. The 
500D potentiometer is the lowest Radio 
Shack stock value; a 100Q value is more 
appropriate. The filter output and the radio 
signal combine to drive the output audio am- 
plifier through level control potentiometers 
and series resistors. This resistive network 
prevents the tuning aid signals from feeding 
back into the data controller. 

Alignment 

For this, you need an accurate space/mark 
frequency reference. It's ideal to use a signal 
generator with a frequency counter. You can. 
however, also get signals from the data con- 
troller. The PK-64 has a software calibrate 
mode by which you can transmit both space 
and mark frequencies over the mike output 
lead. A counter permits reading the frequen- 
cies directly off the screen. A third, less accu- 
rate method, derives the tones from a CW 
signal on the radio. This assumes your radio 
has a digital readout accuracy of 50 Hz or 
better. 

Calibrate the space tone by placing the 
Morse switch in the open position to leave 
only the single tone, and then connecting the 
reference tone to the radio input, You then 
compare the two combined audible tones, 
using the phones or speaker and adjusting the 
trim potentiometer Rl to zero-beat the tones. 
To switch to the mark tone, turn Ql on tem- 
porarily, with a 500Q resistor connected be- 
tween the 12 V supply and the open Morse 
switch (2.2kQ junction). Mark reference 
comparison is made by adjusting R3 for zero- 
beat of the tones. 

Op amp frequency adjustment is best made 
with an oscilloscope. Adjust R5 to equalize 
the space and mark tone amplitudes. Switch* 
ing transients should be barely perceptible. 




Photo B. Front panel of the tuning aid, 

An oscilloscope, however, isn't essential. 
You can make a fair adjustment by first turn- 
ing R4 for minimum switching frequency 
(3-4 Hz), and then adjusting R5 for equal 
audible space/mark tones. 

The switching frequency is not particularly 
critical. You can increase the frequency by 
adjusting R4 until the sound is definitely less 
like that of the nominal packet signal, and 
then lower the frequency a bit. 

Easv To Use 

Just tunc the HF rig to a packet signal. 
If, when you turn up the synthesized sig- 
nal, you get a tone pair similar to the received 
packet signal, you know you* re dead -on! 
In just a few moments, that long-distance 
packet text will start scrolling across your 
monitor. , 



John W6!OJ t a ham since 1933, has con- 
tributed to amateur publications since 194 L 
His career in R&D included radar develop- 
ment at MIT during WWIL John holds 10 
patents and has written nwny construction 
articles on UHF transmitters. Since his re- 
tirement, his hobbies include abstract paint- 
ing. For more info on his article, please write 
to John at 770 La Buena Tierra, Santa Bar* 
bara CA 931 1 /. 



CI 
C2 

C3, C4, C5 
D1 . 02 



PARTS LIST 

0.01 pF, metal film 

0,001 |iF, for 2,1 10 Hz mark tone, disc ceramic 

0,001 [if plus 470 pF for 1 ,600-Hz mark tone 

0.1 gF, metal film 

1N914 



RS 272^1051 
RS 272-126 

RS 272-125 
RS 272-1053 
RS 276-1 122 



Q1 


MPS 3904 


RS 276-2016 


Q2 


MPS 2222 A 


RS 276-2009 


R1 


10kQ potentiometer 


RS 271*218 


R2 


27kQ for 2,31 Hz space tone 

27kD T plus 10kQ for 1 ,800-Hz space tone 




R3 


50kQ potentiometer 


RS 271 -21 9 


R4 


1MQ potentiometer 


RS 271 ^229 


R5 


500Q potentiometer 


RS 271 *226 


R6.R7 


5kQ panel potentiometer 


RS 271-1 740 


U1 


556 dual timer 


RS 276-1 723 


U2 


741 operational amplifier 


RS 276-007 


PC board 


3ft x2ft Inch 


RS 276-1 68 


\C sockets 


1 4- and 8-pin 


RS 276-1999 and 276-1995 


Fixed resistors are Vi-watt* 5% unless otherwise noted. 









I 



I 
I 
I 
I 



r please send infor- 



mation on your line of amateur 
antennas to: 



NAME 



AOOHESS 



CITY 



STAT1 



ZIP 




One Newtronics Place 

Mineral Wells, Texas 7B067 

(917) 325-1386 



CIRCLE 269 ON READER SERVICE CARD 

73 Amateur Radio • October, 1989 81 



Ne 



Number 25 on your Feedback card 



IV PRODUCTS 



Compiled by Linda Rerteau 




Product Of The Month 

THE WILL-BURT COMPANY/TMD SERIES 700 MASTS 

TMD, a division of the employee-owned Will-Burt Company, 
has a new line of pneumatic telescoping antenna masts especial- 
ly designed for amateur radio. With this mast, you can quickly 
retract your antenna for service or esthetic concealment, support 
on-site emergency communications* and set up for mobile and 
DXpedition operation. Fast set-up and teardown, and minimum 
effort. 

Pricing begins at $2600 for the TMD 8-30-768. nested height 
7**9", extended height 3Q\ and weight 170 lbs. The Series 700 
masts are free-standing, made of heat-treated aluminum alloy 
tubes (five sections) with stainless steel fasteners, with all exteri- 
or surfaces anodized and sealed. Keyed tubes maintain position, 
and each mast section and non-locking collar has low- friction 
synthetic bearings. For more specif (cations and model informa- 
tion, write or call TMD, PO Box 900, Orrviife OH 44667-0900. 
(216) 682-7015, Or circle Reader Service No. 201. 



CORRECTION: THE CHALLENGER DX-V 

In the description of last 

month's Product of the Month, 
the Challenger DX-V from GAP. 
Antenna Products, Inc.. there is 
an error. The Challenger, made of 
aluminum and stainless steel, 
weighs only 15 pounds — not 50 
pounds. We apologize for this 
error and any inconvenience it 
may have caused you. 

Please see the September 
issue for more information on this 
unique, elevated GAP. launch 
antenna, or contact GAP, Anten- 
na Products, Inc., 6010 Bfdg J, 
North Old Dixie Hwy.. Veto Beach 
FL 32967. (407) 388-2905. Or cir- 
cle Reader Service No, 209. 

&2 73 Amateur Radio • October, T989 





KENWOOD USA 

Kenwood's new compact FM 
transceivers are now available. 
They run 50 watts, and feature 20 
memory channels. DTMF micro- 
phone with control functions, re- 
mote control head accessory, and 
a bright amber LCD display. You 
can control the radio with the 16- 
key TouchTone, multi-function 
microphone. On the TM-231A, 
coverage is extended 2 meter 
(136-174 MHz receive) for MARS 



CORPORATION 

and CAP, with modifiable transmit 
range. The TM-431A covers 450 
MHz (35W) and the TM-531 A cov- 
ers 1200 MHz (10W), 

Suggested retail prices: TM- 
231 A, $460; TM-431A, $470; TM- 
531 A, $570, Options include the 
digital voice recorder and the RC- 
20 remote controller. Kenwood 
USA Corporation, 2201 E. 
Dominguez Street, Long Beach 
CA 90810. (213) 639-4200. 




SHURE BROTHERS INCORPORATED 



Shure SmartAmp 1 " 
RF amplifiers are de- 
signed to inexpen- 
sively boost transmit- 
ter output power and 
range of low-power, 
two-way radios. The 
mobile SmartAmp in- 
corporates protection 
circuitry with LED in* 
dicators for RF over- 
drive, high VSWR, and thermal overload. In shutdown, the input from 
the transmitter bypasses the amp circuitry and goes directly to the 
antenna output. 

Other SmartAmp features include fused supply voltage leads, a mas- 
sive aluminum case, heat sink, and rugged construction, SmartAmps 
come in different frequency ranges and power ratings, FCC Type Ac- 
cepted, Prices range from $435 to $777. Shure Brothers Incorporated, 
Customer Service Department, 222 Hartrey Avenue, Evanston fL 
60202-3696. (312) 866-2553. Or circle Reader Service No. 202. 



CONTACT EAST 

A complete assort- 
ment of tools for ser- 
vicing computer sys- 
tems, personal com- 
puters, terminals, and 

printers is available 
from Contact East™. 
This Computer & Pe- 
ripherals Service Kit 
contains a complete 
assortment of smaller 
nutdrivers, hexdriv- 
ers, and wrenches, RS-232 cable tools, a duplex outlet tester, a keycap 
puller. IC inserter/extractors, and reversible retaining ring pliers. 

Over 40 tools, a small parts storage box, and optional test equipment 
fit into the black Cordura case, The case also features a document 
pocket, and two other pockets, with flaps and Velcro fasteners. Model 
047-ZCD-B is $275. Contact East, 33$ Wittow Street South, PO Box 786, 
No. AndoverMA01845. (508) 682-2000, Or circle Reader Service No, 203. 




continued from p 59 



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Figure $. 24-hour propagation chart. This shows you the current time 
and the MUF (Frequency vs. Time) for the pointer or country location 
chosen on the DXCC map. From this you can determine propagation 
conditions for the part of the wortd you want to work. 



Figure 4. MUF/Area map. You enter the upper frequency limit, midpoint 
frequency, and tower frequency limit, in MHz. The program makes 735 
catenations for locations spaced evenly over the map display, showing 
various MUF ranges. 



several times to reach this present minimum 
standard. 

The system clock must be set to GMT to get 
the proper display on the maps. Station lati- 
tude and longitude must be entered, as well as 
the current solar flux (available from WWV at 
18 minutes after the hour), These settings are 
retained in a default file for the next cold 
startup. 

What You Get 

The mam program is 150,067 bytes (Ver- 
sion 1,3} in size. Also included are four files, 
DXHt.LIB through DXH4.LJB. The Great Cir- 
cle map creates file MAPxxxx (MAP4371 in 
my case). There is also a mint system folder 
that supplies Finder 5.3, The program is writ- 
ten in a compiled BASIC, which probably ac- 
counts for the large size. It also contains a lot 
of data. Speed, in most cases, is more than 
adequate for the purpose. 

Good Points 

The program delivers what it promises. I 
really like the scroll bar with the guide selec- 
tions on the right. This helps preselect where 
to go in the list (see Figure 1). More programs 
should do this. This program fs much handier 
to use than looking up the information in a 
magazine or a book. The price is certainly a 
bargain for what is delivered. 

Suggestion 
You can't locate a country by name to find 



out the callsign prefix. You have to scan the 
prefix list . II you point and click on the map you 
get the bearing, distance, etc., but not the 
country or prefix. (Admittedly, this is a major 
assignment and I do not consider it a faultf) 

A Bug 

Alt large programs have faults or r perhaps, 
' 'growing pa ins/' I was first issued Version 1 . 1 
to review and found a number of pro- 
gram bugs. I alerted Randy Stegemeyer. 
however, to my comments on these problems, 
and he quickly issued me the updated Version 
1.3. I am pleased to report that all but one 
of the program bugs are gone in this latest 
edition. 

The remaining problem occurs when the 
program first generates the Great Circle map 
on my QTH. The program "hangs" (stops run- 
ning) when I use my QTH latitude (43,5) and 
longitude (71,3), yet it worked fine using any 
other numbers. My present solution is to use a 
slightly different number (change by degree) 
for longitude or latitude, and run again. Randy 
is looking for a way to correct this problem. 

Drawbacks 

Any use of desk accessories or playing 
around with the window resize will screw 
up the screen display. This is not a problem 
with the program, but rather with the way that 
the Mac system uses these features with 
a BASIC program. The main menu provides 
a manual reset reset selection to restore 



the screen display when this happens. 

I haven't been able to try Mufti Finder with 
this program because of the limited size of my 
computer. Anyone with a Mac SE will be able 
to check this out. 

None of the data is in revisable tables, so if 
any of it changes (he program will become 
obsolete. This is a problem only if the DXCC 
country list or the Soviet Oblast" data 
changes. 

Final Impressions 

The only truly unpleasant problems I have 
found are the use of desk accessories with the 
program and the MUF/Area/GL problem. This 
seems to be the type of program I would like to 
have running in the background. However, 
from the bugs found, I wouldn't buy the pro- 
gram for that purpose until I checked it out 
with the author. None of the bugs are what I 
would call serious because no loss of user 
data is involved, except perhaps for the MUF/ 
Area/GL problem. 

Oblast" chasers will find the program very 
useful. 

The code practice works well if you need 
practice on code groups. Its value to the pro- 
gram should be considered as a nice little 
extra touch, and not a reason for buying it. 

For those of us who don't like to squint at 
tables in a magazine and like to have the up- 
to-the-minute DX forecasts using current solar 
data, this program rates a place in your Mac 
software library! 



H 



Number 37 on your Feedback card 



AM HELP 



We are happy to provide Ham 
Help listings free on a space avail- 
able basis. To make our job easier 
and to ensure that your listing is 
correct please type or print your 
request ctearty f double spaced, 
on a fuif (8V2 " x 1 1 ") sheet of pa- 
per. Use upper- and lower-case 
tetters where appropriate, Also t 



Your Bulletin Board 

print numbers carefully — a 1, for 
example, can be misread as the 
letters I or i or even the number 7, 
Thank you for your cooperation. 



Would someone please help 
me? 1 need a diagram for a Clegg 
Mark 3 2m transceiver and for a 



Regency HR-2B 2M transceiver. I 
will gladly pay for copying ex- 
pense and postage. 

Manuel Varela XE3EA 

Calfe13-Ari7 

Prado Norte 

Merida, Yuc. MEXICO 



scan. I am willing to pay for a copy 
or can copy and return originals. 
Thank you. 

David Maynard WA3EZN 

508 Southf ield Drive 

Maumee OH 43537 



I need schematic or service in- 
formation on a Regency monitor, 
Model TML-1, and a Tennelec 
Memoryscan scanner, Model MS- 
1. I also need programming infor- 



l need the manual and schemat- 
ic for the EICO Signal Tracer Mod- 
el 147. I will pay for copy and 
postage, or will copy and return. 
JohnWoehr!eW6KV 
151 Monroe Dr. 
Palo Atto CA 94306 



mation on the Tennelec Memory- 

73 Amateur Radio • October, 1989 83 



Number 26 Oft your Feedback card 



The Quickchanger 

This makes mixed-mode/band operation a breeze 



by Howard E. Cann KA3MRX 






When I was bitten by the 
packet bug, I bought an 
AEA PK-64 TNC to use with my 
C-64 computer Soon I discovered 
thai, in order to switch from HF to 
VHF, I had to plug and unplug 
radios, mikes, and wires. A real 
hassle! 

Time and Labor Saver 

To solve the problem, I designed 
and built the Quickchanger, an in- 
teface box that lets you switch 
a single mike, a TNC, a phone 
patch, and two speakers, all to either HF, 
VHF, or off. This is done with the row of six 
three- position DPDT toggles on its front 
panel. 

Parts for the Box 

I bought a 4" x 2" x 5" meta! box to hold 
the Quickchanger, along with six DPDT 
mini-switches, various mike jacks, and RCA 
jacks to fit my microphones. See Figures 1 
and 2 for the schematic, and the front and 
back panel control and connector placement. 
Be sure to use shielded audio cable both in- 
side and outside the unit. 

The upper position for all six switches is 
for VHF, the lower position for HF, and the 
center position is **ofl\" To go from VHF 
packet to HF packet, flip the two packet 
switches to the lower position, then change 
the parameter on the TNC to HF. To go to 
voice, switch the two PK switches to the cen- 
ter ("off*) position, and flip the mike switch 
to the either HF or VHF. 

The only problem with the Quickchanger is 
some distortion in the audio when using the 
processor in the transceiver. You could easily 
fix this with filtering capacitors. (I didn't 
bother modifying mine since I don't use the 
processor,) 

Mode Changing** a Snap! 

Now, in an instant, 1 can switch modes and 
radios quickly and check for DX easily, tn 
fact, my DX count on packet is headed to- 
ward the CC mark with the help of the 
Quickchanger. 

You need only a mike connector to start 
operating the AEA PK-64, but some TNCs 
need accessory software, connectors, and 

84 73 Amateur Radio * October, 1989 




r 



an interface. When TNC shopping, 
don't be wowed by the advertis- 
ing—read the small print care- 
fully to find hidden costs for extras 
thai are actually required items. 
With a happy purchase, you'll 
be off to a good start with the 
challenges and rewards of packet 
radio ! 



77i£ KA3MRX Quickchanger. 



Parts List 

1 4* x 2" x 5" metal box 
6 DPDT mini-switches, center "off 
3 chassis-mount mike jacks 
5 RCA chassis jacks and plugs 

1 headphone jack 

2 shielded mike cables 
1 shielded audio cable 



« i 



Howard Cann KA3MRX has been 
involved in radiocommunica- 
tions for 30 years, but finally 
decided to get his ham ticket when he was 
a missionary in the Caribbean, because 
that was a more reliable link than the 
telephone! He currently works as a build- 
ing contractor. He is also an emergency 
communications coordinator for Somer- 
set County in Maryland. His other interest 
include boating and flying. You can write 
to him at Route l t Box 146. Weswver MD 
21871, 



HEADPHONE JACK 

PK JUJOIO 




Figure 1. Wiring for the Quickchanger. it takes an hour or less to put this together! 



MIME 



PK 
KM 



PATCH SPl 



OFT 



A a ® <§> 

SwHTChlS *iTH OFF 
tCMTfR 



s*z 



<§> 



P* 
R 



^r 



headphone: 

© 

JACK 



^^" 



PATCH MIKE VHF 



Kt - i -: 



P* &* 




aUQJQ audio 

OUT l hi IN 



YMF Nf OUT OUT 

Q €) © Q © 

PEC SPi SP2 .«*" 

J- 



CABLE TD " 4*C* 

TO Mint JACK 




SCA JACKS 



Figure 2, Front and hack panel of the Quickchanger, showing port and control placement. 



1990 
CALLBOOKS 




THE QSL BOOK! 



Extending a 69 year tradition, we bring you 
three new Gallbooks for 1990 wltn more 
features than ever before, 

The 1990 North American Catlbook lists the 
calls, names, and address Information for 
over 500,000 licensed radio amateurs In all 
countries of North America, from Panama 
to Canada including Greenland, Bermuda, 
and the Caribbean Islands plus Hawaii and 
the U.S. possessions. 

The new 1990 international Catlbook lists 
500,000 licensed radio amateurs In the 
countries outside North America. It covers 
South America, Europe, Africa, Asia, and 
the Pacific afea (exclusive of Hawaii and the 
U.S. possessions). 

The 1990 Calfoook Supplement will bv oub- 
llshed June 1, 1990, with thousands of new 
licenses, address changes, and call sign 
Changes received over the preceding six 
months. Thfs single Supplement will update 
both the North American and international 
Call books. 

Every active amateur needs the Call book! 
Fully updated and loaded with extra 
features, the new 1990 Caiihooks will be 
published December 1, 1969, Order now for 
early delivery when these latest Call book are 
available. See your dealer or order directly 
from the publisher, 



aNorth American Callbook 
Incl. shipping within USA 
Inch shipping to foreign countries 



$31.00 
37.00 

533.00 
39.00 



D international Callbook 
incJ. shipping within USA 
incl* shipping to foreign countries 

o Callbook Supplement, published June 1st 
incL shipping within USA $13.00 

IncL shipping to foreign countries 14.00 

SPECIAL OFFER 

D Both IM.A. & international Callbooks 
IncL Shipping within USA $61 J3G 

Incl. shipping to foreign countries 71.00 

************ 

Illinois residents please add 6Vz% tax. 
Ail payments must be in U,S* funds. 



RADIO AMATEUR 




lltoolc 



INC 



Dept, Q 

925 Sherwood Dr.. Box 247 

Lake Bluff , I L 60044, USA 



Teh (312) 234-6600 




ORCLE 31 ON READER SERVICE CARD 




VadComm 



Advanced Technology 
Enduring Value 



IfeW* 



! PC-320 / TNC-320 controllers 




PC -320 features . . , 

■ Dual modems for optimal VHF and HF operation 

• Appears as regular PC serial port (COM 1-4) - operates with 

any terminal program just like an external TNC 

• Dual Powered - operates from PC or external power Contin- 
ues complete operation even when the PC is turned off 

• Personal Message System- the most advanced personal mail- 

box available mciuded at no extra charge 

» Displays on-screen HF tuning indicator and simulated LEDs . 



Announcing the next gen- 
eration of packet controllers 
for the serious operatorl 
The new inboard PC-320 
(shown), is designed to work 
with all PC/XT, PC/AT, and 
Tandy 1000 series compu- 
ters. The TNC-320 outboard 
controller offers many of the 
same high quality features! 

PC-320 

$ 209 95 

TNC-320... »1 94.95 

(W»ted & Tested 1 Year warranty 1 * 

Fqt complete tnto A specifications 

Calf i$13t B7* 2980 To Order C&' 

Toll Free: 1 -800*223-35 11 

MrffOr Cretfrf Cards Accepted' 



PacComm * 3652 West Cypress Street • Tampa, Florida 33607 
Ptease send U PC-320 O TNC-320 □ More Information □ FRE E Catalog 

Name . Call 



Address 
Slate 



_ Zip 



Card" 



Exp Date 



I 
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i 
i 

i 



MONEY BACK GUARANTEE! Add S4Q0 sfttpptng handling per order Ft residents add6°n sates tax 

Major Credit Card gwe number, expiration and stgnanire FAX. 813-87? 8696 



CIRCLE 152 ON READE* SERVICE CARD 




Butternut 
Verticals 



Butternut's HF 
verticals use 
htghest-Q Tuning 
circuits (not lossy 
traps*) to outperform 
all mull i band designs 
of comparabfe size' 



Model HF6V 



■80 40 30. 20 15 and 10 m#< e js 
automatic bands witching 
•Atfd-on k,i io* 17 and \2 merer) 
available no* 
•26 ft la* 



Model HF2V 

•Designed for [he tow- band DXer 

* Automatic bandswilching on 80 and 
40 me lens 

■Add-on umls for 160 and 50 or 20 
meters 

32 1e*i 'all may be lop loaded for 
additional bandwidth 



For moft information j** your 
Of wnt? for a rnp* brochure 



ti 



BUTTERNUT ELECTRONICS CO. 



405 East Market, Lockhart. TX 7S644 



73 Amateur Radio • October, 1989 85 



Uncle 



Wayne's Bookshelf % 

NOW, the popular electronics and amateur radio books you 've J J 



r\ - 



Aw right, a f ready! 

been hounding poor old Uncle Wayne for are here! Now you can build up your 

hamshack library with these soft-cover favorites . . . 



i 





OiPB ■ The Packet Radio 
Handbook 

At Jonathan J., Maya K&.IT 
. .an escelfent piece of work 
Weil worth reading fur both the 
experienced and the «w [u<Li 
leer the definitive guide to ama- 
teur packci operation ' 

-G* so Reedy W1BEL 

Onh iU.95 



03C09 ■ Shortwave 
Clandestine Confidential 

frv firrry L. liexler 
Fascinating reading —new honk 
cm vers jJI clandestine broadens 
iftg. country by country -lelJ* fre- 
quencies, aihef unpohhshed infor- 
mation — spy —insurpen**— freedom 
frghicrs — rebel anan. hi %i radio— 
secret radio — coven* all Cuncrrt 
pg M teal Km- 84 pacrs SA.9S 



AMATEUR 
kADIO 




QIBftf * The Beginner's 
Handbook of Amateur 
Radio— 2ndEdlton 

by Clay l.tnter 
Combines theory ind prat Ike in jo 
ea&s -10 -under stand format, and 
provides lufimiwluii for choosing, 
and i mulling radio receivers and 
transmitters, antennas, irzmtnn 
sion lincv and tesl equipment 4flf) 
pago. :«l iltu^raikinv SI*. 95 



:■■%■■■. -Maplibrary *t Radio \ matt ur CaHbook Inc. 

Include*; I Prefix Map of the world 4-color 40 * x 28 ' 
I Map of North Arcicrica4~cojof Mi* \ W 
I Grcal Circle Chan of the World 4 color 30" x 35* 



I World Alius d color 2(1 pages 



S 12,00 



ARRL BOOKS 



Six FIus Exciting Amateur Radio Fiction Book* 



AR5095 ■ SOS At Midnight ..., $ 5.00 

AR.soi ? ■ CQ Ghost Ship .....,„,... S 5.00 

ARH20I * DX Brings Danger $ 5.00 

AR50.1 ■ Death Valley QTH ..... 

AR5048 ■ Grand Canyon 0S0 

AR5064 « Murder toy QRM ,. , . r 

A R I4g * Set of 6 Tompkins" Books . 



>!■■■ 



■saap*a-*q 



, ..S 5.00 
. ..S 5.00 
. . . $ 5.00 
. S25.00 



ARZZCK) * Antenna 
Impedance Matching 

*T Witfrtd % Varan 

For the advanced amateur, antenna 
design engineer, and technician 
This i% probably the nvM compre- 
hensive boot eser wrrticirt oo (tie 
use of Smith Cham in volving 
impedance matching problem*. 

SJ5.00 



AR0433 * FCC Hide Book 
Invakuilik- as a 'study guide fef tlic 
regulators material found on the 
ct*m\ and as a handy reference. 

S5,00 

AR2 197 -Data Book 

Thiv hand> reference u a valuable 
awl us the RF dcssign engineer, 
teshnicun. radio amateur and cv 
pertmemer Comitiooh wed u- 
h!cv charu. and Cbenc hard-io-fe- 
tnemher foxmuta*, arc found tn thit 
mewjr SI2.D0 

ARAjMI ■ Interference 

Handbook 
Tins, 2-^fpci^c bnok is written from 
iin Rl ) iletfth*« peripflctive and Is a 
diar> of Kls experience in Kolvtng 
interference probk-mi i 12.00 

ARtnw • Tune in the World 
Bookun! $12.00 



ARlh62 * ARRL 1989 

Handbook 
The I^OO-puge \i\%\ Mith eddinn 
tofjainaovcr 2 I0D tables, fi^rci. 
and fhariY The HaaJfrtwi t\ 
packed *ilh eomponenl di*j and 
awAtrBctifiti anickn $2 1 ,00 

ARtuu: - Solid State 
Design 

Solid Sttth Daiftn facback lull p| 
good, ha mi; information'- 
circuit defifrta and their isppl i. .« 
tions. and dtscripricms of revt-iv 

ers. tniii*iiniEter\, rxiwer supplies, 
jnd tc^ couipmcnl SI2.00 

\R20h? • ARRL Antenna 

Book 
The 4R8t ttriramt Book fcpft- 
tenis the bcu and rnosi higt»J> re 
ended informal Km onvMcnfia fun 
damenteK. tranimission Irrtc^, 
dcM£n. jnil consinaction of wire 
antenna* 118.00 

AR1G86 • ARRL Operating 

Manual 
The AKftf Operating Mimuai is 
|i,j. ked witii iiiitpiinjiinHi on how to 
make the beM u-x of your station, 

itidiny: i titer [iujing honie com 
puurr\. OSCAR. VHF-UHF. did 
tfrimtf SI 5. 00 



ARi2?0 * Log Book- 
Spiral 



S2.50 



1 1 A422 • Antennas 

byJahnKmut. W8JK 
CoVCII (intcrtna ihcoiy and design 
Assumes some maihenuEKdl back- 
ground in algebra. Clearly written 
with etptafutorv dta^rams Well- 
ujtted for sdf-sitidv and traiatng 

$5*95 



Circuit Scrapbook II 

hy Formt At. Mimmi t III 
Prom the articles in tha book you 
will learn how-to Uifonmation that 
will cftltbte you io l'\|h'I'iI]Ilti v, i\h 
MOSfti. analog, and di^imJ cir- 
culls, laser diodes, and nnro dec- 
ironies! Sl?^95 

iiihM4 • 44 Power Supplies 
lor Your Electronic Project 
byRohtrtJ Train* rand 
Jonathan |_ Mayo 
The boot is wmien at the bauc 
lc%d. perfect for i be *vp inner The 
reader » given enoDgth clc ctr nr t ic 
theory lo undcrMand The conoepU 
cj^plinned thnotighout l he book 
_^ 115,^5 

IOW020 - N6RJ Original 2nd 
Op by Jim ftnfferty N6RJ 

A lew edition In an casy-io-usc- 
"wheel" formal, Simply dial l he 
prefix and instantly hj*i? ^tillable 
Beaoi hujdin^\. Contincnl idcnliFi 
cations. Zone idrnfication. PosraJ 
met, and more tit. 95 



<#D22 * The World Ham Net 
Directory 

by Mikr Itirawrii 
New— second edition nov, o\ct 

60T) net lisungs. This bmi mtru- 

diKcv ibe speciaJ interest ham radio 

network* and shows you when and 

where you can tune them in. $9.95 




02m: • The Digital Novice 

fyr Jim Gntbh% k^FA 

Your guide tu the raiciitatliig 
worlds! ol iom mimical ion ihai hit w c 
iii-i . n k-illiI rnr thousands of lona 
leur radio operators. Now ym can 
learn abmil c frvthmg truro Mofm? 
code to the latest in packet rattu* 
teebnoincy SK.95 



05A95 • Easy- up Antennas 
for Radio Listeners and 
Hams by toward At. \tdl 

Would you like to Icain how to 
construct low-cost, easy -to-ercct 
antennas? £tm-up Anirnnai wdl 
hdp you do j u.a that ST6.95 



01 D4fl * DX Power; 

Effective Techniques for 
Radio Amateurs 

by tugrnt 8. Tilton K5RSG 
256 pages. IUi Hum tat ions. 

Sift (Mi 



< I2C30 • The Commodore 
Ham n s Compani on 

by Jim Gmbbs K9F.1 
1 60 pages uf useful i n formation on 
sciecfiag a Commodore coenpoter 
for the ham shack, where to find 
npeoaliied p rogr a m *, the Corn- 
modorepacLei connection, and 
more! $9.95 

05C2S - Basic AC Circuits 

hvStantty ft. Ftrfuttt 
John Rawlins 
A step by slcp approach for tru.- 
licginning attllknL, technician, or 
engineer. Covers concepts, icmi?!, 
and mutheinatics rci|uired to under- 
stand AC circuii pruhkms in an 
easy to read formal. 

«4 + 95 



AA226 * Operating An 

Amateur Radio Station 
This booklet b designed to answer 
ihc basic question* ihr beginner 
may haw. Equipn^nt. anlcnna^, 
and procedures are Covered , $1 .00 



AR22S« * First Steps In 

Radio by (kwx G*M*w WIFE 
Scries of QST arocles You wrU 
I'rnd basic explanation* of circuit 
components: Sec these componenis 
assembled into praciical crrcuir> 
and xe how the circutu maif up 
your r aJ io &rar I5.M 



ARt^l • Transmisalon 
Line Transformers 

by t>r r Jtrry Srvick 
f hi.-i hook covers type* 0j wind- 
ings, core rnaienaK. fractional-ra- 
tio windings, ctficiences. 
muiiiwjrvding and aerial itunskirni- 
tT%, biiluns. Iimitationv at high 
iinpeuVnce beveH and test equip 
mem $10.00 



AR(H^>4 * Antenna 

Compendium 
Materials on vertical*. quads T 
lorffK. Vaps. reduced lite anicn- 
n_u. baluns. Smtfb Chans. Amen- 
na polar lution, and other intefct- 
inguibiects. * 10.00 



AK04SB - W1FB s Antenna 
Notebook 

by Doug IhfWaw W1FB 
TelU Iin* io get the best perform 
ancc out of unobtTusivc * ire amen- 
tm and venkals and how in bnikf 
tuner and SWR bndgo W.OO 



ARRL License Manual 
Beg inning mih Tunr tn thr Wafid 
Htrlr Ham Rod*** for the %m »ce and 
progressing through the criticall) 
iin lantwii iRRJ Uctfiar tfumi.il 
series tor the Technician tbri»uuh 
Estra Chi*., yini wili find p.i.Vimjj 
each cs urn ulcincni a snap I There 
a\-: Licciojilc tt'Jtt erxpkLii.Hiuois n\ 

ihc material covered rIobj wnii 

FCC question pmjb and answer 

keys 

AB01A3 ■ Technician/ 

General Class License 

Manual SS.00 

.ARiHihf. * Advanced Class 

License Manual 45 ,00 

MC239I • Eatra Class 

License Manual S* .00 

AR04I0 • Yagi Antenna 

Design 
Hum fimfat published a sench »i 
artu'Jc* on Yagi?., Tne nUrtefial 
irorti itnvsc arucle> (hat Kprvu'nu d 
here wi4s polished and ^pionkd I", 
Dr UwSQfl 1 15.00 

AR2073 • Novice Antenna 
Notebook 

Novices will leant, an>on^ other 
things, how antennas operate, and 
whir jotcrns their effecmentw 
for ihofl- and long-distance com 
TfiunivAlu»fi SHE .00 

ARiui- • ARRL Repeater 

Directory 19&9-1990 
"HuS edition i» I4 r t larcL-i and in 
dink'* hum 475 beacons covering 
frequencies from 14 MH/ to 24 
GH/. Vuii'Ll «Im- HiuI khvi-r I I 
regul&l iL'pcatcr I i 5vt i n-; s jnd over 
2200difipcaJert SS + 00 

AR2iJK,t i Complete OX'er 

byBabLocktrWVkSl 
You 11 learn how to hum DX and 
how to obtam hard-to-fet QSL 
cards $10*00 






*JR0477 • Low Band DXing 
Trus book ibovis ytiti hew to meet 
the thai [cage* of the different 
formi, of 160* &G\ and 4fJ meter 
propagation *nh effacthn: antcn- 
aaS, equipmrnk and operatitig 
stralegiei. $10.00 



AR203A • Vour Gateway to 

Packet Radio 
Filled wiih miivr motion for all ama- 
tears, iho. boc4 lellv everything 

j need tn kruiw abiiui this popu- 
lar ne» mode: btw to gel .urted. 
equipment Vim need* and more 

SIO.OO 

\R03«0 ■ Tune in tne World 
with Ham Radio Kit 

Tunr in ihr lA»rU with Ham Radio 
toa* put the fun bacl mlo learning 
vi hat Amateur Radio is all about 
\ ko imluded is tvu» C'-^O tape cas 
SCtttS. One Lapc leaches Lhe code. 
iIil- other provides proctkc 

1 15.00 

AR2I71 • Hints and Klnfco 
You are *ure to find the answer to 
that irkks pnobkm thai has been 
boiherrnf you Ideas for w-utng up 
your gear for comfortabie and cffi 
CieM operation S5.M 

AR210V. SaielUte 

Anthology 
Youll find the laiesl mformation 
on OSCARs9lV0Ugh I 3 is ucll a> 
the RS said I lies, lnlorrnaiion on 
iIil' uKcofdigir.il model, tracking. 
amcnrias, RUDAK. mlcroconipot- 
er.andmoref S5,0o 

ARflCUb • Satellite 

Experimenters Handbook 
Under one cmer is what the Aim- 
teuT Radio Opcratifr needs to know 
uf order in communicate through 
OSCAR satellites S10.00 



05H24 * Radio Handbook, 
23rd Edition 

William I. OrrWtiSAi 
Thil hook is filled wiih K40 page* 
-■■I everything you wanted to know 
4K.n1 r.ulu> cummumcation You 
will get an indtf prh \tuds of AC ' IK' 
fundamentals, S.SB. antennas, am- 
plirters. pimer supplies . and more 
$29.95 hard cmrr ord* 





- I 


MASTER 
HANDBOOK 

tooi 1 

wuurnCAi 

ELECTROfJiC 
CWCUTTS 

1 "****" | 







UKKO - Master Handbook 
of 1001 Circuits- 
Solld-State Edition 

by Kendall Webster Sr.txum* 
With this outstanding reference in 
hand, electronics hobby iM* and 
professionals will never have to 
search for schematics again. Conv 
pleirl v updated, the book t* iBur- 
uuchly imkried and all 1001 | 
imb are deariy Ulustrated 42U 
pages SI9.95 soft cover 



Q\Riil * WorttS Press 
Services Frequencies 
(HTTY) 

by Thomas Harrington 

W&Ofift 

A cooipreliensive niLinu:il covering 
Radiotclclypc. news moniloriiig- 
COfltalM all information— antenna. 
receivers, terminal uriilv, plu% 
Three es tensive frequeiK'- 
Covers A5 Woild Press Scrsjces 
broadcasiing in English. l The 
Ongirul Press Book ' S4 paj-es 



SL95 



05f&* • First Book of 
Modern Electronics Fun 
Projects 

Edited by An Satsbrrg 
Looking fot 3 way to hau' tun. 
tm rcase sour technical expertise* 
and isVifl money — all at I he U > ■ 
tlnii ■'' Rtis unique compendium, 
chuck toll ol projects, will vlmw 
yini tiow SI 9.95 



0SC%3 * Commodore 64 

Troubleshooting & 

Repair Guide 

Jrjr R&hcrt V Brenner 
This hook will guide vou step by- 
Hep through the complexities of 
making simple repairs to your 
Commodore o4 $I9;95 



ost -Jn - C64/1 28 Programs 
tor Amateur Radio & 
Electronics byJmephCnn 
The electronics hobbyist, pro 
grimmer, engineer, and icchnictan 
will enjcis the lask^onemed pro- 
eram\ for amaieur radio and dee- 
tromes m this book 114,95 



\sam • Solid-State Projects 
VouCsn BuEtd 

by Rudolf F. Graf 
George J. Whale n 
Have yov searched for challenging 
innovative projects, imagi natively 
if signed j rid ski I J fully denuded (0 
siimulate yiHjr own creative dunk- 
ing:'* If so. i hut book was written for 
ytm* SID.95 

03RG2 •RTTY Today 

by Dave lucrum K41~WJ 
1 Ih* new •inil only up-lo-dali: RT 
TV hoot in existence Coverv all 
facets of RTTY— RTTY mi Home 
Computer*— mom cwnprehcfuive 
RTTY guide ever puM tshed Fu 11 > 
illustrated A muM fur RTTY tarn. 
I?: $H.*5 



h J\f5* * GGTE Morse TUtO* 
Bopp> djsk tor IBM PC, XT, AT. 
and companies Learn die Inier- 
nulinnul Morse lihJc or improve 
• r capabilities- One diskette will 
lake you from beginner through ex- 
tra das> in easy self- paced lessons 
Standard Of Farrtswonh mode 
Code speeds from I to over 100 
words per minute. £20.00 



02CJ0 • Th* Commodore 
Ham's Compamon 

byJimGnthbtk9FJ 
160 pages of useful information on 
selecting a Commodore computer 
lor the hum shack, where to 11 ml 
■specialized prog ranis, the Cnm- 
modorc -packet connection, and 

S9.95 



U5E53 * ABC's of Electronics 
by Eari Jacob Waters 
Wtiiien for anyone wanting to 
leant the btfaki of clectrofiK v, dm 
it a comprehensive. *cll illustrated 
look at the fundamentals M clcc- 
(ronicsand cieetrame applications, 

$12.95 

05519 * Shortwave Radio 
Listening with the Experts 
by Gerry L. Dexter 
Do you bit tor lon£ huurs in from of 
u radio receiver listening to faint 
sounds and noises? Then you're a 
SWLer of DXcr. 2nd you can pfob- 
aNy use s»me help $22.95 



III A 343 ■ All About Cubical 
Quad Antennas 

b* William Orr W6SA& 
Stuart (<>» an W2LX 
The "Clastic" on Quad design, 
theory, construction* operation. 
New feed smd matching sy&tems. 
New data. £ u .95 

I0A344 * The Radio Amateur 
Antenna Handbook 

by Wdimm Orr W6SAIS 

Stuart ( 0% an W2LX 

Yugi henm (henry, construe! ion, 

operation. Wire hcams- SWR 

curses. Matching systems. A 

■ musi ' for senoua DXeis * 1 1 .95 

UM346 • Simple, Low-cost 
Wire Antennas for Radio 
Amateurs 

by William Orr W6SAJ/ 
Stuart Cowan W2LX 
All New 1 Low-cost, multi-hand an- 
tennas: inexpensive heams. ^In- 
^ iblc antennas fur hatns in 
"tough" location*! NewdniA, 

SI 1.95 

I0AM2 * All About Vertide 
Antennas 

by WWwm Orr W6SAI 
Stuart Cowan W2LX 
Effective, low -com verticals 10- 
160 m. -DX. mulnkund. compact 
verticals for small spaces; ground^ 
ing. Lcsl equipment, lightening 

$10,95 

KIA347 • All About VHF 
Amateur Radio 

by Wdliam On- W6SAI 
DX propagation. VHF Yagi and 
Quad beam*, repealers and ho* 
they work. OSCAR satellites and 
how to use them. Si 1 .95 

ns 738 • The 555 Timer 
Applications Sourcebook 
with Experiments 

by Howard M. Berlin 
This book »> about tht- S55 limer. Il 
wilt show you how to use it by itself 
and with niher solid Mule devices. 

S9.95 

09V 1 1 - The Basic Guide to 
VHF,. UHF Ham Radio 

by Edward \t. Sail 
This book provides 11 first rale in- 
troduction to life on the 2.6 and 
I 25 meter hands as well as 23. 33. 
and 70 CM $6.95 



* Basic Electricity/ 
Electronics 

by Robert R, Manvdlf 
In litis basic electricity ; electri>nics 
series of leithooks. a modern pro- 
grammed format is used to present 
the material m a logical and easy- 
Ni - understand way. 
05HH * Vol. 1 introduces the stu- 
dent to the basic concepts of circuit 
lundamcntals. $11.95 

05E02 • Vol. 2 (How ACDC 
Circuits Work) This volume builds 
on the basics. Il gives detailed in- 
formation on series and parallel 
circuits: effects on inductance, ea* 
pacttancc. and transformer action. 

$11.95 



uspcM • Crash Course In 
Electronics Technology 

by Louis E. Frenzet Jr. 
With a proven format of pro- 
grammed instruction, this book 
teaches you the basics of electricity 
and electronics in a step-by -step, 
easy-to- understand fashion. 
$21.95 

01 B033 ■ Talk To The World: 

Getting Started In Amateur 
Radio by James P. Dui KJJD 
ami Morton Keyset ftSMK 
Provides informal ion and practical 
lips on obtaining 11 novice license. 
Authors take the mystery out of 
technical and procedural aspects of 
hamradjn $14.95 



itffiM * One Evening 
Electronics Pro|ects 

h\ Calvin R. Graf and 
Richard S. Goss 
16 projects that can be assembled in 
• simple home woffishop. a voltage 
delector, >ol id-stale telephone bell, 
n iransistor audio amplifier, and 1 3 
others. This is an easy to under- 
stand. Myoyabfe guide to complet- 
ing basic electronics projects — 
w ith just one evening "i work. 

$8.75 

<iKWK7 - Weather Satellite 
Handbook 

by Dr. Ralph E, Taggart 
Dro. Taggart has wntten [his book 
10 serve both experienced amateur 
satellite enthusiast and the ncw- 
Lurner. Amateur weather satcliile 
activity represenls a unique blend 
of interests encompassing electron- 
ic, meterologv. and astronau- 
tics $l»,95 

05P67 • Mastering Packet 
Radio: The Hands-on 
Guide 

by Dave Ingram K4TWJ 
Packet radio is the hottest, most 
rapidly expanding area of amateur 
comntunicaiions. Written for the 
CiniBteur L'rnhusi;isi . mastering 
Packet Radio will put you on the 
cuuing edge of this digital commu- 
nicaiHHis resolution $12.95 




THE WORLD $4.00 



.... .......^ — ...>._ J ..--> J ._ J . 




hi Ml"' •-•^ 



0IT0I ■ Transmitter 
Hunting: Radio Direction 
Finding Simplified 

by Joseph IK Moetl K$OV 
and Thomas S. Curiet 
WRbVZZ 
! Vi pages. 24K iliustrations 

$17.95 

I5D005 + Shortwave 
Directory [5th Edition) 

by Bob Gn>ve 
Ntrw recognized as the standard of 
reference for North American 
shortway listener*, this DXer's 
hihle is crammed with up-to-date, 
accurate frequency and user infor- 
mal ion from tO KH/ to 30 MHz 

$14.95 

is so } • Communication* 
Satellites (3rd Edfion) 

by Larry Yarn Ham 
Includes chapters on channeliza- 
tion band plans* transponder iden- 
tification, iniernalionat satellites^ 
even a history of earth satellite de- 
velopment $ 1 1 , 95 



tnso4 • The Hidden Signals 
on Satellite TV 

by Thomas P. Harrington 
and Bob Cooper Jr. 
Hew book snows and tells how to 
lime in the many thousands or Tele- 
phone . Data, Tele*, Teletype, Kac- 
similc Signals on most or ihe TV 
Satellites, covers equipment. 
hookups, where to tune. Only book 
coverLng these secret stgnaU on the 
utcltiles, plus all Mibcarner*. 234 
pages, $19*95 




06S57 * 1009 Paaaoort 10 
World Band Radio 
fry Inttrnmtkmal Brvadcatitmg 
Serncts* Ltd. 
You can have the world at your 
fingemps. You II get the latest sta- 
tion and lime grids, the I9g q 
Buyer's Guide and more 416 
page*. $14,95 



How can the World's Best DX Map cost only $4.00? Ofrvt- 

ou.sEv . j serious blunder which you should take advantage of 
before wc discover ir. This is the only world map in black 
and white so you can color in th£ countries as you work ibem! 
Further, il has almost ail of the official J ARU 400 countries 
on ic, which no other map at any price has 



- 



CODE TAPES 

tW unrMi-r to tht n< • n *dv hnv -Ha-ha u to malr the rode \o ttnffir tu ftatn that 1 1 '1 
* im-pm4ii*m. Hrrr* nk tht -« rffrf j both t vde cvmft* — Hni <rf rhmmadt t f t umi 
kme ga**» their i^«m th** mpJus >r» thattrmt mar k 1 Jmiurw^rm^ M« 
f*i)p4r are uhle m +tufr thnrnfh thr Scmcr trtt afirtqmJoir fett mtn thtrw kemn 
rurh on GtXrtit 4tnf Dit Sridkler Ftnpt* mht have f 1 1 tn up on \Xber code cmtnei 
Und this, attr dpef thirjrth in a jiffy Caiing uftfr yrrur Grnt'ttit t If J iitumt time, t/tt tft* 
H<irL Hrtnkff and fOU 'ti tw tkerr hf fore vim knnw a. A mirrtt xhiHiltJito it. WttrnifiR, 
JChtpn rvde afmeif imurlahl) appears W> omit irrrpamhtr, irmrrsnhlt. perma- 
■W hwmm ifiMftTji (•itttt H'atnr acyrpti An twsptmntmUt\ ^hairier _for emwhtnf 
mm* happrm tr tkotr mht'ffrepvmismi etmgh ft ► *s* the l 



r 

■ 



1 

■ 




AMATEUR 
RADIO 



ATTN: Uncle Wayne 
Forest Road 
Hancock, NH 03449 



Uncle Wayne's Bookshelf Order Form 

You may order by mail, telephone. Tax, or our Bulletin Board. AH payments are to be in US 
funds. Please add $2.50 for shipping and handling for all orders. Allow 3 weeks for delivery . 



73T05 "tenesiV $5.95 

5 wpm— This is ihe beginning 
U|n\ taking you ihruu^h ihe 26 let- 
ter*. L0 numbers, and necessary 
punctuation, complete *uii prac- 
ticc evers step of the was. The ease 
of learn ut£ gives confidence even 
to the faint of heart. 



7TT13 'Rick Breaker" 45.95 
I J + wpni— Code groups ugain. at 
;i brisk 13 + wpnvsu youll he real- 
ly at ease when you sit down in 
front of a steely -eyed volunteer ex- 
aminer who tlarli sending you 
plain language at only I 3 per 
You'll need: this extra martin to 
overcome the sheer panic universal 
in tnosl lest situations. You've 
come this Car. so don't gel code shy 
now! 



73T06 "The Stickler" S5.95 
ft+ wpm— Thts is the practice tape 
lor those who survived ihe 5 wpm 
tape T and "s also the tape for the 
Novice and Technieian licenses. It 
a comprised of one solid hour of 
code. Characters are sent at 13 
wpm and spaced at 5 wpm. Code 
groups Lire i^nlircly random cllartiC- 
lers seni in groups of five— defi- 
nitely not rncmorizabk! 



Item# 


Title 


Qty. 


Price 


Total 






















































i 


















Marne 




Shipping 
TOTAL 


2.50 


fttr*wrt 







1 

■ 
I 

I 



1 



7 JT20 " ' Courageous * + %S . 9$ 
20 + wpnt—Cciiigratulttlfitltl 
Okay, the challenge of code is 
what's gotten you this far. so don i 
ouit now, Go for the Evtra cLass 
license We send the code taster 
than 20 per It's like wearing lead 
weights tm your fcei when y^m run; 
you'll wonder why ihe examiner is 
sending so slowh* 



I 
■ 

■ City 

TOTAL $ 



State 



Zip 



DAE DMC DVISA uCheck/Money Order 
Expiratfon Date 



1 

| Card? 

1 Mail: 73 Magazine. Attn. Uncle Wayne, Forest Road, Hancock. NH 03449 



Telephone: (603) 525-4201 

FAX: (603) 525-4423 
Bulletin Board: (603) 525-4438 



I 
I 

I 

■ 
I 
I 



Number 27 on your Feedback card 



Keyword index 



■ w I + * + 1 



... 96 
. 22,38 



/ssue #349 



i + _ _ 



u, 



27C64 chip 
556 IC dual timer 

56Kb modem 

6526 chip 
68HC 11 controller 
74HC14 . 
74HC374 . . 
74LS3&3 divider 

80C166 

AEA PK-64 
AEAPK-67. 
AEAPK-232 .... 

AEAPS-186 ,. 

AMD7910chip 

Ampro 286 

AppleTalk network 

ARPANET 

ARRL ncxQde 

Australia 

bandwidth, verticals 

Bell 202 modem . 

BM/Mac 

cable TNC/radio interlace: . , 
earner detection circuit 
mod/kit ............ 

Challenger correction ..... 

Chevenm In tern at J. Net ..... 

CMOS 68000 

code practice . . , »-., 

Commodore ■ ♦ , 16, 

CTCSS correction 

Cycle 22 

OB-9 connector 
D8-25 connector 
Digicom > 64 
DRSr 



......... 



51 
80 
42 
26 

48 
... 51,52 
51 

52 

28 

... 80.84 

52 

51.52,73 

28 

26, 51 , 52 

49 

73 



_ _ _ - 



DX countries list 

DX< low-band 

DX software 

Flodraw 

FT-21 1 

G3 9600 FAX 

G8BPQ, John Wiseman 



* * * * # 



66 

72 

59,83 

...99 

...73 

38 

62 



Lacadives 

LAN 

Macintosh 59 P 68. 69 K 73 

mailbox capability 30 

MAX232/235 Chips 34 

Maxim Integrated Products ...... 34 

MFJ I270TNC 13 

MFJ 1278 controller 14, 40, 50 

Microsats ...«.*...♦♦ 49 

microwave packet * . 28, 30, 38 



gain, verticals , 70 

GRAPES, tnc 42 

ground system for verticals 70 

Home-Brew IV results 11 



i ■ ■ ■ ■ 



11 

54, 60, 61 

44 

.... 68 
...... 40 

... 50-51 

* * * OCp "-C 

1- t ■ ■ - m %1*T 

* T ■ ■ ■ ■ ^F^B" 

59 
24.34,84 

92 

103 

32.40 

13.35,36 

24 

20 



. . . ■ . 



* * 



Hong Kong 

IC-22S mod .-.*■■■. 

IV»*™ • fi'M I 4 4 «- V I F I f f -4 1 1 * 1 t V ■ 

tC-761 secret bandwidth . . 

ICOM HT . . , 

IFR 1200S Service Monitor 
India .............. 

interface PCflCCVR 
International Crystal 

Ireland 

Japan 

JK 1 LOT Terakoya software 

JK1RJQ software 

K2UK. Dr. Edward N. Ludm 

K9NG modem 50. 54 

KA3MRX, Howard E. Cann . . . 84 

KA9ELV, Ted Orude 24 

KA9G TCP/IP 62,68 

KA9Q. Philip R. Karri, Jr. ..... 42.62 

Kaboom keyer correction . 92 

KA-Nocte .... 61 

Kantrontcs KAM ... 14. 18. 32 T 40. 52 

KBGCDQ. Mike Kabala 34 

KB1UM, Michael J- Geier 13 

KDKFM-2016A ... 13 

KE4PC, Michael S. Dooley 31 



96 
31 
48 
98 
41 
44 
96 
20 
31 
94 
38 
38 
38 
92 



mobile operation . 

modeless programs 
modem mod ..... 

MUF chart . . .. 

Multi Finder software . 
mufti mode controllers 
murder inquiry ,,.... 
N3EUA. Bdale Garbee 
N4AQG, Joe Davidson 

N4PLK modem 

N4RVE, Steven K. Roberts 
N60YU, Doug Thorn 



- i ■ ■» 



., 48 

68 

26 
103 

69 
14,30.32 

11 

..2a 

...... 32 

* + + * ■ ■ fr»# 

48 

68 

N7CL, Eric Guslafson 50 

NESSSICdock 44 

Net/Mac 68 

NET/ROM 6. 22 T 29, 62 

networking 6, 22, 28, 60 

NOS TCP/IP , ... 38 

null-modem 36 

PacComm Micropower-2 TNC . 48 

PacComm TINY-2 52 

packet, basics 6. 14-19 

packet graphics 32, 38 

packet signal synthesizer 80 

parameters for packet 18 

PC/Node 22, 62 

PCPA 20, 22, 44, 62 

propagation . 103 

Public Brand Software . . 99 

R96F AX chip 38 

R96MDcttip 38 

ROSE 6 T 29. 61 



RS-232 port schematic correction . 92 

RS-232/TTL interface . . . . . 34 

RS-232/TTL Interface kit 36 

schematic design software 99 

Shockley. William ... 11 

software 16, 24 

Sweden . . , . 94 

switching circuits ........ 13, 32, 64 

SX-64 24 

TAPR 28,50,51,52,62 

test clip troubleshooting 98 

TMC 3105 chip 26, 51 , 52 

TCP/IP . . 6, 22, 38, 61 , 68, 69, 73 

TexNet 6, 29. 54. 56, 58, 61 

TEXTNET-iP 54-58 

TheNet 22 

TPRS address 58 

TPRS modem 54 

traps in verticals 70 

TTL tevef signals, definition 34 

TR-2500HT.„_ 41 

TS-440S IF unit mod 98 

VCs and datagrams 60 

verticals, QRM 72 

W1 GV, Stan Gibilisco 70 

W2UP. Barry Kutner 24 

W6IOJ, John Reed 80 

WA1 LBP. David Cowhig + , . 38 

WA4DSY modem 22 

WA4DSY modem kit 42 

WA8DZP, Dewayne Hendricks 68 

WARC bands 11 

WB6RQN, Brian 

Lloyd. 6,14,20,40,60 

WS6WKB H David Bartholomew ... 30 

WB8EHS, Daniel Kautz 59 

WB9CWE. Michael Simmons .99 

wormhole . . 22 

WW5 103 

XR*2206/221 1 chips 26 

Yaesu 290 48 

yagi. vertical ... - 72 

Z80 microprocessor 28, 51 , 54 

• PC. Ekctromcs «• 

I52 f^-Cimiitt $5 

ITS PicifjcCibkCoJrx 75 

68 Pienpheji 73 

145 Q50 Software . 71 

31 Radin Amateur Callbook 85 

23 1 Radio Amaieu r Qllbook 6 1 

150 Radio Worb 77 

34 Ramsev Hkctnuucs 57* 

• RawRadk) 91 

115 RF ConnectKHi . . , 36 

254 Ross Distributing 64 

73 S-F Amateur Radio Service 41 

• Sangean America . , . 95 

132 Satellite City . . 79* 

36 SCRAMBLING NEWS 64 

• Silicon SohflkKB 95 
274 Smile} Antenna Co. Inc. . ...... 73 

• Soft Ugjrt Mfg. Co ,64 

244 Software Systems %9 

250 Software System* 91 

102 Sparrow Hawk Communication* 64 

5 J Spectrum CommuoKatiofla ... 75 

183 Spectrum I mematioru] . 41 

• Slow Mountain Engineering ■ 64 

• Summitek ...» 89 

377 Syspec. Inc 97 

28 TDSyitems 75 

136 Unadilla Antennas Mfg Co. . 71 

• Universal Antnepr Radio 69* 
79 Vanguard Labi ......... 29 

• VHF Communications 75 
191 W&W Associates 31 

38 W9INM Antennas. ,, 64 

• Wi-Conim Elftdniiijci , . 91 

• Yattu Electronics Corp. CV3 

* Advertisers who have contributed to the 
NAitonai IndusifV Adviwr> Cunrmmee <MAC». 



Advertisers 



Number 2S on your Feedback card 



Issue #349 



?? 


80USCAM 


. . , 69 


355 


Ace Commit nications 


97 


1 


Advanced Computer Control 


45 


65 


Advanced Electronic Applications . 


. IW- 


126 


Aero Data Systems ... 


15 


88 


Aerospace Consulting ... 


69 


194 




51 


• 


Allied Appliance & Radio 


97 


• 


Amateur Electronic Supply . . 


>. 37* 


m 


AmaiBTiT Radio School . 


... 2* 


314 


Amentron . , 


15 


• 


Ampirejnc 


19 


6 


Antenna Specialists. 


?7 


5 


Antennae West 


79 


302 


Antennas West .... 


77 


107 


Antennae West 


91 


236 


Antennas WeM 


H 


309 


Antennas W< it . 


... 89 


90 


Antennas West 


89 


304 


Antennas West 


41 


89 


Antennas West 


...15 


82 


Antcnnoi 


, . 53 


271 


Antique Radio Classified 


. . . 77 


338 


Ashuro fTC 


^9 


* 


Associated Radio 


89 


16 


Astrcn Corpomion 


39 


243 


AXMJr* 


75 


158 


Azimuth Communications 


27 


360 


Azimuth Qunniumcatmrw 


p p p 4a h' 


■ 


B & B Instruments 


iiH 


53 


Barker & Williamson 


67 


41 


Barry Bectronki Corp. 


31 



42 Btlai Company 

* Bnan Beczfcy K6STI 

170 Bockmastcr Publishing 

7 Buckmaster Pubhshmg 

* Burghardt Amateur Radio 

* Bunemul Electronics 

356 C & S Sales, Inc 

* CB City international .,....., 
1 57 Cleveland Institute of Electronics 
343 Conmpuas Corp. .... 

99 Communication Concepts. Inc. 

121 C ouiuaukka riofts Electronics . . . 

10 Communicaimns Specialist .... 

15 Comtelco 

12 Connect Systems T 

306 Crcaavc Control Products 

147 Data Com International 

239 Digital Radio Systems Itw 

15 DopplerSyojcms 

I IZ c- Hr Yost 

29 1 Electron Processing 

* Engineering Consulting 

268 Etched Call Sign Cups 

172 G&GELECTROMCS * 

73 Gap Antenna Products 

46 Giinhief v Covers Plus 

339 GGTE 

17 GLB Electronics 

72 Glen Martin Engineering 

» Grapevine Group . 

3J6 Great Circle Maps 

326 GT1 Electronics 



■j % m | 



79 

53 

41* 

15* 
23 
85 

. 53 
. 64 
63 
53 
. 75 
. 43 

■ 

. 75 

I 

.. 63 

63 

95 

W* 

77 

75* 

., 15 

29 

71 

13 

77 

, 19' 

67 

.. 2.1 

.. 89 

15 

91 



57 Hamtronks, Inc. 

• Heam Co. 

» Heath Co. 

269 Hustler. Inc 

354 ICOMAmenca 

• Iitcrcon Data Systems 

100 Interconnect Specialists 

• ImtTTiaiMfuS Radio . 
272 J un's Electronics 

92 K^) 

• KentttwdU S.A. 
Corporal ion ...... 

9 L.L. Grace 

23 Larscn Antennas 

2 LEB EnterpriMis 

277 Lindsay Pubticmons 

278 UnJitc CAE, [nc 

363 Mac Irak Soft*ire ...... 

25 Madison Electronic Supply 

• Maggi ore Electronics Lab , 

101 Mascom, Jnc 

55 Meadow [jkc Corp. 

2-1 1 Media Mentois ... 

44 Metro Printing 

24 MFJ Enterprises - 

86 MFJ Enterprises 

348 Micro Com pu ler Concepts , 

• Micro Control Special ilic.s , 

25 Midland Technologies 

1 87 M ission Communications & 

Consul ting . . 

163 Mobile Mart 

• N6KWQSL Cards 
151 Naval Electronics 

• Nemal Electronics 

1 Omar Electronics 

• Orion Business I nl ' I 

• PC. Bectrotucs 



21 
93 

..n 

81 
CV2* 
. 101 
.. 55 
15 
. IDL 
. 19 



9,i0.I2,CV4* 
47 

101 
36 
63 
. 97 
,49 
.77 
89* 
. 63 
75,97* 
63 
4 
5 
53 
79 

... ^7 



64 
67 
. 79 
. 64 
. 19 
64 
67* 
71- 



88 73 Amateur Radio • October, 1989 




N umber 29 on your Feedback card 



FECIAL EVENTS 

Ham Doings Around the World 



CHICAGO !L 
OCT1 

The Chicago ARC will hold its 
semi-annual Open House be- 
tween 12 noon and 5 PM local 
time, Live demonstrations of 
equipment will be shown by ex- 
perts. Dean (312) 869-HAMS or 
George, (312)545-3622. 

ROME A 
OCT1 

The Coosa Valley ARC will 
sponsor its Hamfest at the Rome 
Civic Center. Free admission. 
Camper parking available, but no 
hookups. Tables $6. outside 
spaces $3. Amateur exams begin 
at 8 AM. Reservations requested 
but walk-ins accepted. T.J. Free- 
man NC4G 26 Conn St.. SE, 
Rome GA 30161. (404) 232-2830. 

HAMMOND IN 
OCT1 

The Lake County ARC will 
sponsor its annual Hamfest at the 
Hammond National Guard Ar- 
mory. Free parking. Limited ta- 
bles $5 ea. Admission $3.50. VE 
testing with novices free and walk- 
ins welcome. Overnight accom- 
modations close by. Talk-in on the 
Lake County ARC repeater at 
147.00 or 148.52 Simplex. Ken 
Brown WD9HYF. 91$ Chippewa, 
Crown Point IN 46307. (219} 663- 
5035. 

YONKERS NY 
OCT1 

Yonkers ARC is holding its Ham 
Fair at the Yonkers Municipal 
Parking Garage. Sellers: $8 per 
space, bring own table, No ad- 
vance registration . Buyers: $4 ad- 
mission, under 12 free. Talk-in on 
146.865/R or 440.1 5/R, 146.52. 
YA.R.C, PO Box 378, Centuck 
Station, Yonkers NY 10710. Or 
calf John Costa at (914) 963- 1 02 1 
or (91 4) 969-6548. 

ROCK HILL SC 
OCT1 

The York County ARC will spon- 
sor its Hamfest at Joslyn Park. 
Talk-in: 146.43/147.03. York Co. 
ARS. PO 30x4141 CRS, Rock Hi ft 
SC 29731 L 

SPRINGFIELD OH 
OCT1 

The Independent Radio Assoc 
will be holding its seventh annual 
Hamfest at the Clark County Fair- 
grounds. All vendor and swap 
meet activities are indoors. Ad- 
mission is $3 advance, $4 at door. 
Under 12 free. Tables $7 ad- 
vance, $8 at opening. Talk-in on 
145,45/R and 224.26/R. Indepen- 
dent Radio Assoc. r PO Box 523. 
Springfield OH 45501 or call 



Steve Ktipiei KA8QCS at (513) 
882-6521. 

BILOXI MS 
OCT 7-8 

The annual ham/swapfest 
sponsored by the Mississippi 
Coast ARA ts to be held at the 
Point Cadet Plaza. Free admis- 
sion. Talk-in te on 146.13/73. Ed* 
wardL Byrd KA5VFU, 183 1 6 Lan- 
don Rd, Gulf port MS 39503. (601) 
832-3249. 

WARRINGTON PA 
OCT 7-8 

ML Airy VHF ARC Pack Rats 
invite all amateurs and friends to 
the 13th Annual Mid-Atlantic VHF 
conference at the Warrington Mo- 
tor Lodge. Also, come to the 1 8th 
Annual Hamatama, Sunday al the 
Bucks County Drive-In Theatre. 
Advance registration is $5. $6 at 
the door including conference. 
Flea market is $5 per person, $7 
per carload Selling spaces $6 
each. Par Cawthome W83DNI. 
(215)672-5289. 

HUNTINGTON FN 
OCT 8 

The Huntington County ARS is 
sponsoring its annual Hamfest at 
the PAL Club. Free parking, 
Handicap accessible. Admission 
S3. 50 advance, $4 at door. 8-ft. 
tables $5 each. Talk-in on 
146. 085/, 685 and 448.975/ 
443.975 . Jim Covey KC9GX, 1 752 
KocherSt, Huntington IN 46750 

PORTLAND CT 
OCT 10 

The Middlesex ARS an- 
nounces their ARRL/VE FCC li- 
cense examination session the 
United Methodist Church. Ed 
Kerns KN9Y, (203} 342-3400. 

SYRACUSE NY 
OCT 14 

The Radio Amateurs of Greater 
Syracuse will hold their 34th Ham- 
fest at the New York State Fair- 
grounds. Outdoor flea-market set- 
up $3. Indoor flea-market set-up 
$7 ($6 if paid before Oct, 7th), Ad- 
mission $4 before Oct. 1 1 SS at the 
gate, age 16 and under free. 
Checks payable to "RAGS." Pre- 
register for FCC exams with SASE 
by Oct, 7th; write Attn: Exams, 
"RAGS". Box 88, Liverpool NY 
13088. For more info call Ed Swi- 
atlowski WA2URK, (315) 487- 
3417 or Viv Dougfas WA2PUU, 
(315)469-0590. 

WEST PALM BEACH FL 
OCT 14-15 

The Palm Beach County Ham- 
fest will be sponsored by the Palm 
Beach Repeater Assoc, at the 
West Palm Beach Fairgrounds. 



Advance admission is $4, S5 at 
the door. Tafk-in (input/output) 
147.765/. 165. Send SASE to: 
From HAMFEST. P.O. Box 461 r 
Lake Worth FL 33460. 

WAUKESHA Wl 
OCT 15 

The Kettle Moraine RAC Inc. 
will hold its annual Ham/Comput- 
er/Video Fest indoors at the 
Waukesha County Exposition 
Center from 7 AM-1 PM. New, 
larger building. Tickets are $2 in 
advance and S3 at the door. Re- 
served tables are S3 for each 4'. 
Reservations accepted until Oct. 
11. KMRA Club, PO Box 41 h 
Waukesha Wi 53187. Include 
SASE with order. 

COLUMBIA MD 
OCT 1 5 

The Columbia ARA announces 
that its 13th annual CARA Ham 
Fest will be held at the Howard 
County (Maryland) Fair Grounds. 
Admission $4 (spouses and chil- 
dren free). Free parking. Indoor 
tables $20 each for one to four 
tables, $18 each for five or more- 
Each table includes one admis- 
sion. C.R, Whetstone WA3YOH, 
211 Clarendon Ave.. Baltimore 
MD 21208, or call (30 1) 486-2609. 

LIMA OH 
OCT 15 

The Northwest Ohio ARC will 
hold their annua* Hamfest at the 
Allen County Fairgrounds* Camp- 
ing (electricity $7}. All night securi- 
ty. Free parking. Advance admis- 
sion is S3. 50, $4 at the door. Table 
reservations are $8 full. $4 half 
table. Send checks 2 weeks in ad- 
vance. Talk-in frequencies: 
146.07/67; 14763/03: 444.925: 
449.925, For table reservations 
contact WD8BND. PO Box 211. 
Lima OH 45802. (419) 647-6513. 
Handicap accessible. 

QUEENS NY 
OCT 14 (Rain Date OCT 22) 

The Hall of Science ARC Ham- 
fest will be held at the New York 
Hall of Science parking lot. 
Buyers $3 T sellers $5 per space. 
Talk-in 144.300 Simplex link; 
223,600/R and 445.225/R, Steve 
Greenbaum WB2KDG (evenings) 
(718) 898-5599 or Phil Kubert 
N2HYE (212) 777-8648. For VEC 
info: Ann Fanelii WI2G. (718) 847- 
0155. 

WALL TOWNSHIP NJ 
OCT 1 5 

The Shore Area Ham & Com- 
puter Fest will be held at the Al- 
iaire Expo Center (Allaire Airport), 
sponsored by the Garden State 
ARA. Jersey Shore ARS T Neptune 
ARC and Ocean-Monmouth ARC. 
Free parking. Admission: Outdoor 
sellers $8 per 8' wide space (first 
come basis). Indoors sellers $20 
per table by reservation. Please 
make check or money order 
payable to Shore Area Ham and 



Computer Fe$t r PO Box 635 T 

Eatontown NJ 07724, Buyers $4 
advance, (tickets have two draw- 
ing stubs), $5 at the door (one stub 
only). Kids under age 1 2 and X YLs 
free. Talk-in: 145.1 10-600 KC2Q/ 
R; Simplex 146.520. Fly>in fre- 
quency: Unicom 123.0, At Jack- 
son NK20> PO Box 635, 
Eatontown NJ 07724. (201) 922- 
81 21 \ 

SMITHFIELDNC 
OCT 21 

Triangle East ARA will hold its 
1st Hamfest in the Smithfreld 
Moose Lodge, Admission $4 for 
adults. Table and 2 chairs $6. 
Talk-in on 146.88. Send SASE to 
Triange East ARA, PO Box 255, 
Smithfietd NC 27577 or phone 
W2AC (days) at (919) 553-4309; 
KK4YP (nights) (919) 965-9577 
5:30 PM-9 30 PM. 

GRAY TN 
OCT 21 

The Ninth Annual Tri-Cities 
Hamfest. sponsored by the 
Kingsport, Bristol and Johnson 
City Radio Clubs, will be held at 
the Appalachian Fair Grounds, A 
large drive-in indoor and outdoor 
flea market space is available. R V 
hookups. Admission $5. P.O. Box 
3682 CRS t Johnson City TN 
37602 

8ENSALEM PA 
OCT 22 

The Penn Wireless Assoc, is 
sponsoring Tradefest '89 at the 
Yezzi Field. Admission S3 each or 
$7 per carload. Kids 1 2 and under 
free. Spaces $5. Premium or 
2x/3x wide spaces available 
in advance. Talk-tn: 146>52f 
147.00 + 0,6, Steve: (215) 752- 
1202. For advance tickets send 
checks with SASE to PWA Trade- 
fest '89, PO Box L-734. Lang- 
home PA 19047. 

BROOKLYN PARK MN 
OCT 28 

Hamfest Minnesota & Comput- 
er Expo, sponsored by the Twin 
Cities FM Club, will be held at 
Hennepin Technical College, Ex- 
panded double-decker flea mar- 
ket guest speakers, plenty of 
parking. Talk-tn on 146.16/.76. 
Tickets are $4 advance. $5 at the 
door. Send SASE to Hamfest Min- 
nesota & Computer Expo, PO Box 
5598. Hopkins MN 55343. (612) 
474-1529. 

MARION OH 
OCT 29 

The Marion ARC will hold its 
15th annual Heart of Ohio Ham- 
fest at the Marion County Fair- 
grounds Coliseum. Large parking 
area. Advance tickets S3, $4 at 
door. Tables $6. Check-in on 
146.52 Simplex or 147.90/. 30 
repeater. For information, tickets 
or tables contact Ed Margraff 
KD80C, 1989 Weiss Ave.. Marion 
OH 43302. (6 1 4} 382-2608. 



90 73 Amateur Radio * October, 1989 



• ■ 


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73 Amateur Radio * October. 1989 89 



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73 Amateur Radio * October, 1989 91 



Letters 



Number 30 on your Feedback card 



Native American Hama 

Over the past couple of years Tve 
read in 73 about your interest in ham 
radio activity among minorities in the 
US. Recently, the Little Big Horn Ama- 
teur Radio Organization, a ham group 
for members of the country s original 
"minority/" Natrve American Indians, 
has formed. Membership is notlimited 
to Native Americans; hams from other 
ethnic backgrounds, as well as those 
who have an interest in Native Ameri- 
can culture and history, are also wel- 
come. Correal ly LBH includes hams 
from the Cherokee, Crow, Ojibway. 
Oneida, Sioux, and Tling^ tribes, plus 
many non-Indian hams. Its goal is to 
build bridges of understanding and 
friendship between all Native Ameri- 
cans and other people via amateur 
radio. 

Two code nets are conducted week* 
ly to exchange news and interests. 
Both convene each Sunday. General 
class and above operators meet on 
14,057 MHz at 2200 hours UTC The 
code speed is kept to about 15 wpm. 
Novices and Technicians meet on 
21.150 MHz at 2230 hours UTC. This 
net is sfow code speed for easy copy- 
ing. Listen for M CG LBH" followed by a 
general announcement. Net control 
stations are WB0L m Minneapolis, MN. 



From the Hamshack 

and WA2DAC in Peru, NY. WA2DAC is 
also net manager. 

Visitors are welcome and encour- 
aged to check into the nets For more 
information about LBH. contact M. Mc- 
Daniel W6FGE, 940 Temple Sl. f San 
Diego CA 92106: (619) 222-3912. 

Mick McOaniel WSFGE 
San Diego CA 

How Much? 

In todays hi-tech world of wonders 
and high prices, \ can see why the ama- 
teur radio ranks are dwindling. How 
can anyone expect that a no-code li- 
cense wiH change the trend? It's the 
prices thai are the problem. If 73 would 
offer easy-to-construct plans tor CW7 
SSB gear for Novices, you might at- 
tract more people. 

Carl Forsyth KC4IRP 
Charlottesville VA 

Cart, try spending more lime reading 
the magazine Just in '89, we ran a 
number of fine home-brew articles for 
QRP rigs (June and February), and 
many articles on modifying inexpen- 
sive and/or older equipment. Get in 
touch with us to check the article index- 
es for that specific home-brew project 
you want to build— we can likely help 
you*. , deNSfB 



Remember When 
30 MPH was Fast? 

Code is now like a fine old car. You 
enjoy it for its beauty, craftsmanship, 
and esthetic value, ft also gets you 
from point A to point B. The bottom 
line, however, is thai it tsn't normally 
optimal for everyday purposes, 

Barry Goidwater's statement 
("Looking West" June t989) regard- 
ing the code requirement convinced 
me Not everyone needs a fine otd 
car — or even just an older model that 
runs fine. I tike my CW and my trusted, 
smooth-as-velvet f vintage Navy key. 
but I wouldn't expect everyone to find 
one and use it. 

Our hobby is evolving— and so must 
we! 

F. Paul Kosbab NF4E 
Tulsa OK 

Arizona Sunshine 

I would like to publicly thank Senator 
Barry Goldwater for his help. After ex* 
plaining to Senator Goldwater thai the 
Amateur Radio Society at Arizona 
State University had no working equip- 
ment for 30 dedicated members, he 
was kind enough to donate a trans- 
ceiver and receiver to the club, We 
would all tike to express our gratitude 
to this line man. Ham radio will have a 
rewarding future with support like 
we've gotten from Senator Goldwater, 
Matthew Horbund KB7HYF 

Tempe AZ 

Pure Good Fun 
I don't claim to be any better at get- 



ting kids interested in amateur radio 
than any other ham. I never even tried 
with my three boys. So, looking back, 
what was it thai really got them inter- 
ested in ham radio? It might have been 
the time I built them the remote control 
for their HO gauge trains, or It might 
have been when I built the transmitter 
for one of their model rockets, but I 
seriously doubt it was either. Showing 
each of them how to punch in WWV 
and other stations on my Kenwood, 
and operate my straight key with the 
sidetone oscillator, realty peaked their 
interest as well 

But what lit up their faces the most 
was when I let them talk to other hams, 
just like ourselves, in other parts of the 
country, I would suggest simply letting 
youngsters participate, when appropri- 
ate. They learn a tot faster when they 
get to experience it for themselves, 

Bill Garde! N3GQW 
Downington PA 



One of Many Modes 

I view CW as just another form of 
communication, along with phone, 
packet, and ATV. and I feel it should be 
treated as such. If as much emphasis 
were placed on proper and considerate 
Operating procedure and the omission 
of unnecessary power within the 
Novice sectors of the HF bands by indi- 
viduate holding higher class licenses, I 
thoroughly believe that this would be a 
greatly improved hobby. 

James T. Elliott, Sr. N3FWQ 
Baltimore MD 




ow receive or 
leave messages 
with other local hams 
using the 16K Bulletin 
Board featured on the 
smallest TNC available - 
the Heath* HK-21 
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The BBS operates 
under your call with 
simple commands 
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and read the File 
messages currently on 
the system. And the 
HK-2 1 Pocket Packet is 
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Hookup is easy. 
Plug in supplied cables 
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a fast-growing number 
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Number 31 on your Feedback card 



Upda tes 



U, not I 

The correct call for Dr. Edward N, Ludin ot Cherry 
Hilt NJ is K2UK. His celt appeared incorrectly in 
"Letters" in the November 1988 issue, 

C-64 and RS-232 

The following corrections and clarifications are 
needed to the schematics m "RS-232 Port for the 
C-64, " December 7983; the 9V AC that powers the 
circuit comes from pin W t not pin 9; the PB0 pin on 
the edge connector is left f hating; the ground on tC 1 
(7660 voltage converter) ts pin 3; the ground on IC 3 
(the 1489) is pin 7; and, on fC2(the 1488), pins 4 and 5 
are grounded and the output pin, no. 6, is U$R only. 

PL Tone Generator 

Two alterations are needed to the parts list in 
"CTCSS, Fast and Cheap, " August 1989. Add 04 
and C5 coupling capacitors at 47uF each, and 
change the resistance of the VRl potentiometer to 
25 kD. 

Challenger 

See the correction on last month 's Product of the 
Month, the Challenger DX-V t in this month's New 
Products department. The challenger weighs 15 
pounds, not fifty pounds 

Kaboom Microkeyer 

Refer to the schematic in the "Kaboom Mi- 
crokeyer. " pages 28-29 1 in the September 1989 
tssue. Change the values of the capacitors that 
connect pins 3 and 4, and pins 5 and 6 of the 8044 IC, 
to 0.01 mF. Aiso t join the non-grounded lead of the 
600 PiV diode to the collector leads of the two 2N2222 
transistors. 



92 73 Amateur Ftadio • October, 1989 




X-ing, contests, pile- 
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From our recent expedition 
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Proven output power 

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On the chance that someone 
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with only 80 to 100 watts of 
drive, our SB-1000 develops 
more output than even the 
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Designed for today, the 
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"I built it myself!" 

Because you build the 
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A top quality amplifier cost 
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See the SB-1000 and our 
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Number 32 on your Feedback cord 



INTERNATIONAL 



Notes from FN42 

The torch is passed! Just as the 
World Olympic Games generates 
a friendship and bond between 
countries and athletes, so has the 
73 International column between 
countries and ham radio opera- 
tors. The editorial **we ft are sorry 
to announce that our International 
Editor, Richard Phenix, has re- 
tired after many years at 73 
Magazine. The September 1989 
column was his last; 73 Magazine 
and the ham community will cer- 
tainly miss him. 73s to you, 
Richard, and may you find contin- 
ued peace at your cabin at Road's 
End, 

This column will continue to be 
edited by C.C.C. until a suitable 
replacement can be found. 

For those of you who wish to 
send photos for the column, we 
prefer color, but black and white is 
also acceptable. Address alt cor* 
respondence for this column to 
73 International, WGE Center, 
Forest Road, Hancock NH 03449 
USA. 

Roundup 

Australia. The Contest Man- 
ager of the Australian Ladies' Am- 



edited by CCC. 

ateur Radio Association an- 
nounced the contest rules of their 
1989 contest. The contest starts 
Saturday 11 November 1989 al 
0001 UTC and ends Saturday 1 1 
November 1989 at 2359 UTC, 
Further information can be re* 
ceived from the Contest Manager: 
Mrs. Marilyn Syme VK3DMS, 
P.O. Box 91, Irymple. 3498, Vic. 
Australia. 

From Amateur Radio Action 
(ARA) via Ken Gott VK3AJU: 
Some different award books are 
available for those of you who are 
dyed-in-the-wool award hunters- 
Contact the following for further 
information and prices: Amateur 
Radio Awards (2nd Ed.), Sue 
Squibb G1TZU, 36 Frognal Gar- 
dens, Teynham. Sittingbourne 
Kent ME9 9HU UK; Amateur Ra- 
dio Awards (3rd EdJ RSGS, 
Lambda House Cranbourne Rd, 
Potters Bar Hertfordshire EN6 
3JE Great Britian: international 
Awards Guide M.S., Lumban Gaol 
YBGWR J1 Garuda No. 62 Jakarta 
10620 Indonesia; and the K1BV 
Directory of DX Awards, Ted Meli- 
nosky K1BV, 525 Foster Street, 
South Windsor CT 06074-2936 
USA. 



Calendar for October 

1 — National Day, China, Cyprus, Nigeria; Erntedankfest 

(Thanksgiving), Germany 
2— MahatmaGhandt + s Birthday, India 
3— National Foundation Day, South Korea 
4— Independence Day t Lesotho (12th for Equatorial Guinea, 

28th for Czechoslovakia) 
5— Republic Day, Portugal (9th for Khmer Republic, Cambodia 

[Kampuchea], 29th for Turkey) 
7 — Foundation Day, East Germany 
8— Constitution Day, USSR 
9 — Han^Gul Day, South Koreau: Columbus Day, USA; 

Thanksgiving Day, Canada 
10— Health-Sports Day, Japan; Kruger Day, South Africa; 

National Day T Fiji 
12 — Columbus Day, Latin America: Dia de la Raza 

(National Holiday), Spain (22nd for the Vatican, 26th for 
Austria, 28th for Greece) 
14— Young Peoples Day, Zaire 
15— Evacuation Day. Tunisia 
17— Mothers Day, Malawi 
20— Anniversary, 1944 Revolution, Guatemala 
21— Revolution Day, Somalia 
22 — Labor Day, New Zealand 
23— Chulalongkron's Day, Thailand 
24— UNITED NATIONS DAY (Dia de las Naciones Unidas) 
(Jour des Nations-Unies){Tag der Vereintert Nationen) 
27— 3Zs Day, Zaire 
30— Bank Holiday. Ireland 
31— Chiang Kai-shek 1 s Birthday, Taiwan 



[The two "Amateur Radio 
Awards" hooks are likely differ- 
ent— CCC] 

Ireland. An example of ham ra- 
dio generating friendship and a 
bond comes from the May 1989 
issue of the Irish Radio Transmit- 
ters Society Newsletter. Limerick 
Radio Club and the South Jersey 
Radio Association recently an- 
nounced that they have become 
associated as 4+ Twin Clubs." 

The "proclamation' was 
signed on March 1st by the South 
Jersey Radio Association and 
brought over to the Limerick Ra- 
dio Club by Joe Duff in W20RA/ 
EI8GT, a member of both clubs. 

The purposes of the twinning 
arrangement is to promote friend- 
ship between two Amateur Radio 
Clubs with a common interest, ex- 
change valuable information re* 
garding the Amateur Radio Ser- 
vice, and encourage the sharing 
of radio operating experiences 
from both sides of the Atlantic 
Ocean. 

The arrangement was con- 
ceived by Limerick Radio Club 
during their 40th anniversary cele- 
brations in 1986. The South 
Jersey Radio Association was 
pleased to be selected by the Lim- 
erick Radio Club for this honor. 

While the American Club is over 
73 years old, this is the first time in 
their long history that they have 
twinned with another Radio Club, 
and they are very proud of the ar- 
rangement. [This is another won- 
derfui way to develop worldwide 
friendships. Now is an excellent 
time forglasnost'. if your club has 
done something similar, please let 
us know.^CCC] 

Sweden: (Radio Sweden) 
GOODBYE SOS— Distress sig- 
nals sent by ships in the familiar 
dots and dashes of Morse code 
are to become a thing of the past, 
according to the International 
Maritime Organization (IMO). 

From 1993 Morse code will be 
replaced by the Global Maritime 
Distress and Safety System 
(GMDSS). a revolutionary high- 
tech system which sends a dis- 
tress signal at the touch of a 
button. 

The system, which will be com- 
pulsory in ships worldwide after 
1999, has been under develop- 
ment si nee the 1 970s and some of 
its technology is already in use on 
British vessels. 

It works by sending a radio dis- 
tress signal which bounces off a 
satellite to display the ship's posi- 
tion, name, and the time of the 
incident on a coastguard comput- 
er terminal, (Reuter). [Maybe an- 



other good reason for no-code in 
the future?— CCC] 

U.S.A. A letter from S. 
Schwartz KE6XS reports that the 
Chaverim International Net is a 
group of Jewish amateurs (Jewish 
hams?) which meets every Sun- 
day at 1300 UTC on 14.326 MHz. 
Chavenm means friends in He- 
brew. The object is to promote fel- 
lowship among a worldwide group 
of calMns. So far, the Chaverim 
Net has heard from Belize, 
Canada, Israel. Ecuador, Peru, 
and mainly the Eastern part of 
the USA. 

Due to propagation, the So. 
California section is asking all in- 
terested Jewish amateurs west of 
the Rockies to join another 
Chaverim net at 1600 UTC on 
14.326. Hopefully this will also 
include calls from many other 
areas, 




AUSTRALIA 

Ken Gott VK3AJU 

38A Lansdowne Road St. Kilda 

Victoria 3lB$ t Australia 

What's new (or news) in VK- 
land? On the awards front, we 
have a Worked All VK Call Areas 
award which is far and away the 
most popular Wl A Award. I recent- 
ly had a batch of 29 applications in 
one envelope (naturally, a big 
one) from the USSR, about half 
from hams and the rest from 
SWLs, since the award also exists 
in an SWL form. There is also a 
VHF version of it. Recently the 
first VHF WAVKCA award went to 
Yoshiteru Mori JA2BZY. 

Apparently there are lots of J 
hams, including Yosrnteru, who 
only needed the VKG. Suddenly 
the break came— in the form of 
VK9YQS/VK0 on Macquarie Is., 
on 6m. 

Prior to this, I had a phone call 
from a 6m specialist alerting me 
that about 50 J stations would be 
applying for the VHF WAVKCA. 
So far, no great rush— only about 
six applications. But even six is a 
landmark for this particular 
award. Maybe the dozens of 
Japanese stations that made it to 
VK(& on 6m still need some other 
call areas— hard ones like VK9. 
We will see. 

On a more personal level, I'm 
moving the shack. We have a 
targe, solid brick structure de- 
signed as a garage, but never 



94 73 Amateur Radio * October, 1989 



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ORDERS: 1-800-999-0204 



CIRCLE 239 ON READER SERVICE CARD 

73 Amateur Radio ■ October, 1989 95 






used as such. I've had power laid 
on to it and pretty soon will paint 
the inside, install a ceiling, and 
generally fix the place up. The 
biggest job will be getting rid of the 
old furniture in it- 
Then will come a tower. To date 
I've onty had a G5RV. I've con- 
firmed about 160 countries wrth it. 
but the time has come to move to a 
beam. I consider myself semi-re- 
tired. As an economic-cum-what- 
ever consultant, I tend to gear my 
income efforts to my needs. The 
needs are now acute, in view of 
the need of a tower, etc. [Ken is 
presently attempting to ascertain 
the life (dead or afive) of over 70 
awards "offered" in VK. Quite an 
undertaking. —CCC ] 






HONG KONG 

Philip J. Weaver VS6CT 
GPO Box 12727 
Hong Kong 

Phil writes that he contacted the 
Post Office that administers the 
licensing in Hong Kong and asked 
them to approve "The 73 Interna- 
tional Universal Permit Applica- 
tion." He sent us a copy of their 
reply. 

They have no objection to visit- 
ing radio amateurs using the inter- 
national application for a visitor's 
amateur station licence or licence 
under reciprocal agreement in 
Hong Kong, However, the appli- 
cant should submit his application 
in accordance with certain notes 
on their standard application 
form, i.e.: 

(a) The applicant should submit 
the application in person, bringing 
the original copies of the required 
documents for verification (the 
originals of the Radio Amateurs' 
Examination Certificate or pass 




Photo A. JS, VU2JX, making one of the many contacts from VU7JX. 



slip, Passport. Hong Kong ID 
Card, current amateur licence is- 
sued by other administration, etc., 
should be produced for verifica- 
tion in person to: The Maritime 
Services Section, Telecommuni- 
cations Branch, 5th Floor, Sincere 
Building, 173, Des Voeux Road 
C en tral + Hong Kong). 

(b) If the applicant is under 21 
years of age, the licence will be 
issued in the name of the parent or 
guardian, and parent or guardian 
information will be required. The 
parent or guardian will be respon- 
sible for the observation of the li- 
cence terms. 

(c) The applicant should sign 
the declaration provided in para, 6 
of the Hong Kong application 
form, [ The Annual Licence Fee is 
HK$ 150. . . CCC] 




INDIA 

J. Srinivasan VU2JX 

340 5th Main Koramangaia 

Bangalore. 560 034 India 




73 International is pleased to 
announce that J Srinivasan (JS) 
is our new Hambassador in India, 
JS enclosed an article written on 
the team that went to the Lac- 
cadives in March 1989 (VU7JX) 
and emphasised RTTY through 
the BARTG Contest 

DX-PEDJTION TO 

THE LACCADIVES: VU7JX 

"HOW ABOUT PUTTING LAC- 
CADIVES— VU7— ON THE RTTY 
MAP FOR THE BARTG CON- 
TEST?" This early morning call 
from J.S. (VU2JX) to me did un- 
leash a whole chain of the most 
unexpected events. It was 4 
March 1989. 

Within the hour, a member of a 
DXpedition already in the Lac- 
cadives was contacted on 40m 
to check if they would let us 
operate RTTY for the BARTG con- 
test ...but no enthusiasm 
showed up. Before the night was 
out, Nat (VU2NTA) and Vidi 
(VU2DVP) swelled the size of the 
team to a forceful four, 

John Troost (TG9VT), the cata- 
lyst of this idea, was informed 



promptly and the whole RTTY 
clan got to know: the first ever 
VU7 on digital mode! Special 
permits to the islands were ap- 
plied for. 

Passage from Bangalore to 
Cochin, Cochin to Agathi and then 
to Bangaram and back was 
booked. It had to be postponed, 
cancelled and rescheduled sever- 
al times before our arrival, en fin, 
at Conchin ultimately on the 15 
March, wfth bags and baggages 
of rigs, antennae, masts, et al. 

All domestic and business af- 
fairs were rearranged. There was 
nothing in our collective con- 
sciousness except getting to the 
Islands and getting on the air. 
Were we surprised to know that no 
ship was to leave for the Islands 
before 1 8 March, the date of com- 
mencement of the contest! The 
twice weekly turbo-prop flights 
had been cancelled. The heroic 
aircraft needed maintenance and 
recodification, having reached 
the end of its certified life! The 
availability of a helicopter was an- 
noyingly uncertain, and its capaci- 
ty to carry the beam, mast and 
other equipment in doubt! 

The formidable Bernie {SWL 
Bernard Abroa) and vigorous Vidi 
brought in the whole bunch of avi- 
ators to our chambers and saw to 
it that we got into Agathi not too far 
behind our antennae. 

The multi-hued sunset and the 
much wearied team landed to- 
gether on the paradise on earth — 
the Bangaram Island, in Lakshad- 
weep as the Laccadives is known 
in India. 

Can we ever thank enough the 
sporty tourists — foreign and Indi- 
an—who carried the antennae 
and mast literally on their willing 
shoulders throughout their 
cramped flight? Can we ever for* 
get Capt. Krishnan. our pilot, who 
strayed into our shack and stayed 
up well into early morning and lent 







M 






""§'14^; fl 


^fi k_ 







Photo B. VU7JX r s Shack by the Sea- 
SB 73 Amateur Radio * October, 1989 



Photo C VU7JX tribander in Paradise. 



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WHAT! 



An OM of yours borrowed a prized copy of 
73, and now it's among the missing, Let 
Uncle Wayne help restock the issues in 
your almost complete 73 yearly volumes 
from July 1980 to the present. 
Write us today for the copies you need 
from July 1980 to the present only. Sorry, 
but we've sold out all but a few collector's 
copies prior to July 1 980. 

JULY 1980 to present, . .54.00 each 
including postage and handling 



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BOZEMAN. MT59715 (406)566-1 190 

CIRCLE 252 ON READER SERVICE CARD 



Say you saw it in 73! 



73 Amateur Radio * October, 1989 97 



his strength — physical and mor- 
al—as we put the antennae up 
and set out the rigs? 

Utterly unmindful of the strong 
superstition of the Islands of not 
climbing trees after dusk, an ad- 
mirably agile angeJ went up and 
down the sky-reaching coconut- 
trees and strung up our dipoles for 
40 and 80 metres. In the cool 
breeze of the early morn— at 21 30 
hrs UTC {it was 3 AM local time on 
17 March)— VU7JX's first call em- 
anated from the palm-thatched, 
airy cottage, set right on the very 
lap of the loveliest lagoon. What a 
take-off point! What a view!! 
Window to the world indeed!!! 

Thanks* Arasu You and your 
adorable XYL made us feel abso- 
lutely at home right away. Un- 
ceasing (diesel) power and unlim- 
ited hospitality! You and your boys 
are not employees of the resort, 



not stay longer and work all of you, 
out there, beaming towards Ban- 
garam, One h(sw)ell of a pile-up!!! 

The unpolluted air was a magic 
healer; the balmy weather, a ton- 
ic. Every meal a veritable repast: 
succulent tuna, tasty lagoon-fish, 
lender chicken and juicy beef, ev- 
ery morsel delicately grilled and 
caringly offered. The heady palm- 
juice or the chilled beer. . .sheer 
ambrosia! 

The coral Laccadives {meaning 
a lakh of islands), populated by 
graceful people and generous co- 
conut palms, surely wear Ban- 
garam (the golden one) as the 
crown, in shape a doughnut, 
adorned by Lush green and 
cerulean blue waters, miles to 
wade in. swim T snorkel, paddle or 
wind- surf 

Thank you, micromaniacs, who 
write soft-wares on propagation. 



Tech 



Number 38 on your Feedback card 



TIPS 




Photo D. AOA Arctic Ocean Award from the West Siberia DX Club* sent 
by UA9MA. Loosely translated by Bryan NS IB: ' For two-way communi- 
cations (observed) with amateur radio stations of the countries and 
territories of the Arctic Ocean. " 



but our expansive hosts. 

The lights that were switched 
on in the shack in the evening on 
16 March were put out only after 
the antennae were brought down 
and everything packed in the wee 
hours of 24 March. 

What a ready and resounding 
response we found from fellow- 
hams throughout the dxpedition! 
Memorable! A deeply satisfying 
contest of six hundred plus RTTY 
points and around five thousand 
CW and Phone QSOs indeed 
moved us towards forgetting and 
nobly forgiving the intentional 
QRM; but can we ever forget 
those guardian angels ever 
present with us on every band and 
politely policing it? 

Since our QSLs are already ar* 
riving at their various destina- 
tions, our only regret is that we did 



Based on your predictions we got 
onto the contest several hours af- 
ter the start of the contest; and it 
did pay rich dividends! 

Special thanks to you, John 
(TG9VT); but for your not so gen- 
tle-goading, we would have re- 
grettably let this possible DXpedi- 
tion pass us by, A51 can not be far 
for us if you are by our side! 

Reels of strong wire- rope, the 
sturdy antenna-mast and our 
hearty greetings are left behind 
with Arasu, the Manager of the 
Island Resort for you hams, arriv- 
ing there in the not so distant fu- 
ture. 

Must all good things ever come 

to an end? .... Until then. 

73s. Rom VU2RUM Box 4250\ 
Bangalore, India. 

[When do we leave, Wayne?? 

—CCC] 



Secret Bandwidth 

As the product literature indicates, 
when the ICOM 10-761 is in SSB mode. 
its bandwidlhs are 2.4 kHz and 2.6 kHz 
with the filter switch in the "in'" and 
"out" positions, respectively. Howev- 
er, there is a third bandwidth for receiv- 
ing on this radio. Leave the filter switch 
in the "out" position and place the IF 
shift button in the "in" position for IF 
shift, and the bandwidth becomes 3 to 
3.2 kHz wide. 

When using just the filter switch to 
select the advertised wide and narrow 
positions, you receive and transmit us- 
ing both the 9 MHz and 455 kHz tiller; 
when using the above method for wider 
selectivity^ you're apparently receiving 
through the wide ceramic 455 kHz filter 
only, bypassing the 9 MHz filter . Here's 
! he pertinent data 



9 MHz 
FL8G 
FL-80 
By-passed 



455 kHz 
CFJ-4S5K5 
FL-44A 
CFJ-455K5 



Bandwidth 
2.6 kHz 
2.4 kHz 

=* 3 + kHz 



Jim Nance KE4WY 
Douglasville GA 



A Real Turn-On 

If your ICOM with an internally 
switched power suppty turns off when 
you don't want it to, leave it turned off 
and unplug it for about a minute Then 
plug it m and turn it on. Assuming ev- 
erything else is okay with the rig, the 
radio should come back on and put you 
where you left off, because, while the 
power supply has no fuse, it does have 
an auto- protect ion circuit. 

Bill Hickox KB50Z 
Houston TX 



Super Simple Solution 

If you use an IC test clip for trou- 
bleshooting, you've probably discov- 



Pearls of Tech Wisdom 

ered thai the test contacts are so close 
together it's difficult to attach a probe 
without touching adjacent contacts, 
and touching the wrong contact can 
cause damage in some situations. 

If the contacts are long enough, this 
fault can be corrected by bending 
some of them. On one side, bend every 
other contact outward about 45 de- 
grees and bend the remaining contacts 
inward. On the other side, the contacts 
opposite those that were bent inward 
should be bent outward, and those op- 
posite the ones bent outward should be 
left alone. This also makes it easier to 
count to find a particular pin. The photo 
shows how easy it is to attach a probe 
with the wide spacing that results. 

Charles E. Conn KK4CS 
Austell GA 



QSKat30WPM 

High-speed keying is great, but It 
can create problems. When pounding 
code into the Kenwood T3-440S at 
about 30 wpm. the QSK starts to short- 
en transmitted RF signals and you may 
get bad tone reports To correct the 
situation, Kenwood suggests altering 
the delay and hse times by changing 
components in the IF unit (X6Q-130Q- 
00 J as follows: 

Make the value Of resistor R151 
47kO, instead of 1 0kO; make the value 
o* resistor R2G0 tOOkO, instead of 82 
kQ; and make the value of capacitor 
C166 1 pF. instead of 3.3 yF. These 
components are located in the IF unit 
between the optional S SB filter and the 
front edge of the PCB. 

J us si Torhonen 
GH7DC/QH3NWP 
Rllhimaki Finland 



The above items, except 'Super Sim- 
ple Solution" are adapted from Inter- 
national Radio Inc.. 




Using KK4CS'$ solution, you touch only the contact you choose. 



98 73 Amateur Radio * October, 1989 



Number 39 on your Feedbacl card 



73 Review 



by Michael Simmons WB9CWE 



Flodraw 

Drawing schematics on your PC. 



Public Brand Software 

PO Box 51 31 5 

Indianapolis IN 46251 

Price Class: $5 



Have you ever wanted to use your PC 
and dot-matrix printer to quickly 
produce schematic diagrams, but you 
didn't have the software for it? 

For just a few dollars, you can own 
Flodraw, a graphics editor program with 
ready-made electronic symbols, and 
drawing and editing functions. 



ANTENNA 



UDC 



The Price is Right 

Flodraw is shareware, which means 
you can legally copy it from different 
sources for free, or for a nominal fee, and 
evaluate it for your needs, If you don*i like 
it, you can discard it with tittle or no loss. If you 
do like it, you can register with the author for 
$25, or $35 if you want updates and assis- 
tance* 

Flodraw comes on two disks, and works 
with most PC compatibles and primers. You 
don't need a mouse or joystick. Although ifs 
mainly for drawing computer flowcharts, it has 
libraries for electronic, organization, and oth- 
er symbols. Just select what you want from the 
menu. 

The library has 22 symbols for drawing 
schematics. You can modify these and save 
your modifications and schematic drawings. 
The beauty of Flodraw is that you can place, 
move, or edit a symbol, connecting line, or 
group of components very rapidly and accu- 
rately, If you get stuck, you can display the 
help screen by pressing alt-h. 

Creating and Editing Your File 

When you begin, Flodraw will prompt you 
for the name of your file, type of library, and 
printing format. Type the name of your file, 
whether new or previously saved, and select 
the ''Electric' 1 library. 

In the editing mode, Flodraw uses a win- 
dow, which means you only see a part of the 
total picture. As you bring the cursor across 
the screen, the window will move across the 
work area. For rapid movement, you can use 
the pq up and pg on keys, alt-r and klt-l move 
the window right and left. 

If you get lost, you can press F2, the View 
function, for an overview of your whole work 
area with reduced resolution. An on-screen 
ruler helps you pinpoint your location, 

Pressing the r key alternates between the 
two editing modes; text mode and drawing 
mode. In text mode, you can type, move 
blocks of drawing, and call up symbols. In 
drawing mode, you can refine your drawings 
and produce connecting lines between com- 
ponents. 



EARTH 

GROUND 





■5 UDC 



^ 








1 (203 : 3 OHM 
TRANSFORMER 

A 



\l 



AUDI 
OUTPUT 



SPKR 



A simple schematic drawn using Flodraw. 



For example, let's say you want an antenna 
symbol. Place the cursor where you want the 
antenna symbol, press Fioto bring up the sym- 
bols, then press the function key which corre^ 
sponds to the antenna symbol. The symbol 
will pop onto the screen. Made a mistake? 
Press F9 and the symbol vanishes. 

When you're drawing lines between compo- 
nents, the menu will prompt you on position- 
ing the cursor and let you know when to press 
F4 to indicate the line's beginning and end. 

Using the block functions, you can rotate, 
defete, copy, or move symbols or groups of 
symbols anywhere in the diagram you wish. 

Producing New Images 

You can type text anywhere in the schemat- 
ic with a number of font sizes. Some symbols, 
such as the one lor IC, are already labeled. 
You can modify them as you wish. Let's say 
you need the symbol for an iron core choke- 
First, call up the transformer symbol. Position 
the cursor to the left of the unwanted wind- 
ings, and press the spacebar to erase them. 
You now have your choke symbol, which may 
be stored in the library for future use. 

Drawing a nonlibrary item, such as a tube or 
MOSFET symbol, is trickier. You have to call 
up a circle from the menu, then draw in the 
lines with the arrow keys. This is a litlle time- 
consuming, but not impossible, and once 
drawn and saved, you'll have it instantly avail* 
able in the future. 

tf you've saved a circuit on disk that would 
be useful in your present diagram, you can 
use the Merge function to bring it up and place 
it exactly where you need it. 

Printing Your Drawing 

Flodraw offers three printing formats: the 
portrait, 8.5" x 1 1"; the landscape, 1 1 " x S-S"; 
and the large landscape, 16* x 11", or two- 
page format 

As for hardware, printers which support Flo- 



draw are the Epson, IBM, Toshiba, and any 
printer which emulates the graphics modes of 
these printers. My Star NP-10 works well in 
IBM mode, Print times vary from three to nine 
minutes, depending on the type of printer, and 
whether you select single-strike or double- 
strike printing The print quality is quite good- 
Several Drawbacks 

The F9 (Undo) function only works on an 
immediately preceding operation. If you de- 
cide that earlier work needs to be eliminated, 
you have to use the text cursor and spacebar 
or the Block-delete function. These are a Itttfe 
cumbersome, and they don't always permit 
complete erasure of a fine or symbol. 

Also, when you initially place a symbol on 
the screen, it will be perfectly placed for clean, 
easy line connections to other symbols. But if 
you rotate it, its center will shift, and drawing a 
straight line to it from another component will 
be almost impossible. You can get close to 
connecting a line to one of its ends, but you 
may have to draw a diagonal fine to fully con- 
nect. This isn't a major problem; it's just that 
the connections do not look perfect. 

Conclusion 

I found Flodraw well worth looking into. A 
54-page, well*written instruction booklet and a 
15-minute tutorial are included on the disks. 
They provide excellent help while learning the 
software. 

You can download copies of Flodraw from 
some computer bulletin boards, or buy a copy 
for a few dollars from mailorder shareware 
distributors, such as the one listed at the top of 
this review, 



Michael Simmons WB9CWE has been m amateur 
radio since 1970, and especially enjoys 20m RTTY. 
He currently owns and runs a small publishing com- 
pany. Michael can be reached at 101 Harrison Ave. . 
Chartestown IL 61920, 

73 Amateur Radio • October, 1989 99 



Number 33 on your Feedback card 



DEALER DIRECTORY 




Burbank 

Free QSL Cards on orders over S 100! ! Discount 
prices on all amateur products. Open 7 days a week. 
Call our Bulletin Board. ADTECH ELECTRON- 
ICS, 1033 Hollywood Way, Burbank CA 91505; 
(81 8) 845-9203, (818) 846^-2298 FAX, (818) 846- 
6746 Modem/BBS. 

San Diego 
Hard to find parts, surplus electronics, standard line 
items. Hams, hobbyists, industrial professionals— 
from nuts & bolts to laser diodes... Electronic ally 
speaking, Gateway's got it! M-F 9-5:30 Sat. 9-5. 
GATEWAY ELECTRONICS, 9222 Chesapeake 
Drive, San Diego CA 92123; (619) 279-6802. 




Denver 

Hard to find parts, surplus electronics, standard line 
items. Hams, hobbyists, industrial professionals— 
from nuts & bolts to laser diodes... Electronically 
speaking, Gate way' s got it! M-F 9-5:30 Sat. 9-5. 
GATEWAY ELECTRONICS, 5} 15 N. Federal 
Blvd. /F32, Denver CO 80221; (303) 45S-5444. 



DELAWARE 



New Castle 

Factory authorized dealer! Yaesu, ICOM, Ten-Tec, 
KDK, Kenwood, AEA, Kantronics, Santcc. Full 
line of accessories. No sales tax in Delaware, One 
mile off 1-95, DELAWARE AMATEUR SUP- 
PLY, 71 Meadow Road, New Castle DE 19720; 
(302) 328-7728. 




Preston 
Ross WB7BYZ has the largest stock of amateur 
gear in the Intermountain West and the best prices. 
Call me for all your ham needs, ROSS DIS- 
TRIBUTING, 78 S. State, Preston ID 83263; 
(208) 852-0830. 



KANSAS 



Wellington 

We have it! ASTRON, BUTTERNUT, ENCOMM, 
HEATHKIT, GORDON WEST, KANTRONICS. 
LASER COMPUTERS, MFJ. RADIO SHACK, 
TEN -TEC, VALOR ANTENNAS & more. Small 
town service with discount prices. D ANDYS, 
120 N- Washington, Wellington, KS. 67152, (316) 
326-6314* Circle Reader Service 263 for more in- 
formation . 




St. Louis 

Hard to find parts, surplus electronics, standard line 
items. Hams, hobbyists, industrial professionals— 
from nuts & bolts to laser diodes.., Electronically 
speaking, Gateway's got it! M-F 9-5:30 Sat. 9-5. 
GATEWAY ELECTRONICS, 8123 Page Blvd., 
St. Louis MO 63130? (314) 427-61 1 6, 



NEW HAMPSHIRE 



Derry 

Serving the ham community with new and used 
equipment. We stock and service most major lines; 
AEA, Astron, B&W, Bencher, Cushcraft, Hustler, 
ICOM, Kenwood. KLM, Larsen. MFJ, Mirage, 
Vibroptex; books, rotors, cable and connectors. 
Business hours Mon.~Sat. 10-5, Thursday 
10-7- Closed Sun. /Holidays, RIVENDELL 
ELECTRONICS, 8 Londonderry Road, Derry 
NH 03038; (6fi3>434-5371. 



NEW JERSEY 



Lyndhurst 
A full service Ham Radio Store! Discount sales 
and service on most major brands. Monday to Friday 
12:00am to 7:00pm, Saturday 10:00am to 4:00pm 
'4 mile south of Rt3. ABARIS SYSTEMS, 
227 Stuyvesant Avenue, Lyndhurst NJ Q707I; 
{201)939-0615. 




Jamestown 

Western New York's finest amateur radio dealer 
featuring ICOM-Larsen-AEA-Hamtronics- 
Astron, New and used gear. 8 am to 5:30, Sat. and 
Sun. by appointment. VHF COMMUNICA- 
TIONS, 280 Tiffany Ave,, Jamestown NY 14701, 
(716) 664-6345. Circle Reader Service number 129 
for more information. 



Manhattan 

Manhattan's largest and only ham and two-way 
Radio Store, Featuring MOTOROLA, ICOM, 
KENWOOD, YAESU, AEA, SONY, UNIDEN, 
etc. Full stock of radios and accessories. Open 7 days 
M-F, 9-6:30 pm: Sat & Sun, 10-5 prn. We ship 
worldwide. BARRY ELECTRONICS, 512 
Broadway, New York NY 10012; (212) 925-7000. 
FAX (212) 925-7001. 




Greensboro 
10a.m. to 7p.m. Closed Monday. ICOM our special- 
ty-Sales & Service. Also (to name a few): Ten -Tec p 
Yaesu, Kenwood, Bencher, Sangean, B&W, MFJ, 
Alinco, Comet, Sure, Callbooks, Ameco. Frank 
N4AZM, Mae KB41MX. F&M ELECTRONICS, 
3520 Rockingham Road, Greensboro NC 27407; 
(919)299 3437. 




Columbus 

Central Ohio's full-line authorized dealer for 
Kenwood, ICOM, Yaesu, Ten -Tec, Info-Tech, 
Japan Radio, AEA, Cushcraft, Hustler, and But- 
ternut, New and used equipment on display and 
operational in our 40GQ sq.ft. store. Large SWL 
department, too, UNIVERSAL AMATEUR 
RADIO, 1280 Aida Drive, Reynolds burg (Colum- 
bus) OH 43068; (614) 866-4267, 



PENNSYLVANIA 



Trevose 
Authorized factory sales and service. KENWOOD, 
ICOM, YAESU, featuring AMERITRON. B&W, 
MFJ, HYGAIN, KLM, CUSHCRAFT, HUS- 
TLER, KANTRONICS, AEA, VIBROPLEX, 
HEIL, CALLBOOK, ARRL Publications, and 
much more. HAMTRONICS, INC., 4033 
Brownsville Road, Trevose PA 19047; (215) 357- 
1400. FAX (215) 355-8958. Sales Order 1-800- 
426-2820, 



TEXAS 



Dallas 

In Dallas since 1960. We feature Kenwood, 
ICOM, Yaesu, AEA, Butternut, Rohn, amateur 
publications, and a full line of accessories. Factory 
authorized Kenwood Service Center. ELECTRON- 
IC CENTER, INC., 2809 Ross Ave., Dallas TX 
75201; (214) 969-1936. 

Houston 

Hard to find parts, surplus electronics, standard line 
items. Hams, hobbyists, industrial professionals— 
from nuts & bolts to laser diodes. ^Electronically 
speaking, Gateway's got it! M-F 9-5:30 
Sat 9-5 GATEWAY ELECTRONICS, 9890 
Westpark Drive, Houston TX 77063; (713) 
978-6575. 

Southwest Houston 
Full line of Equipment and Accessories, in- 
house services Texas #1 Ten Tec Dealer! 
MISSION COMMUNICATIONS, 11903 
Alief-Clodine, Suite 500, Houston TX 77082; 
(713) 879-7764. 



DEALERS 

Your company name and message can contain up to 25 words for as little as $300 yearly (prepaid), or $175 for six months (prepaid). No 
mention of mail-order business permitted. Directory text and payment must reach us 60 days in advance of publication. For example, 
advertising for the April '89 issue must be in our hands by February 1st. Mail to 73 Amateur Radio, Donna DiRusso, Box 278, Forest 
Road, Hancock, NH 03449, 



100 73 Amateur Radio • October, 1989 




FREE 



IBM - PC 

SOFTWARE CATALOG 



• For Harm. EJecmcal En- 
gineers and Finicky PC 
Users. 
■ Hundreds of programs 
teste*! 10 IDS's rigid stan- 
dards, 

■ IDS'* president is a HAM an J hard to please Only 
30% of the programs submitted for Testing make it lo 
the catalog. 

■ He's also a Cheapskate! ■ 

Frog rums Include: 

CW CODE PRACTICE * CONTEST LOG - accural? 
BEAM HEADINGS • GRAPHIC on-^rsen-ploiting 
CALCULATORS ■ CIRCUIT DESIGN AIDS ■ super 
rested PROPAGATION FORECASTING ■ TERMI- 
NAL EMULATION 

NONE C)F OUR DISKS COST OVER *4.95 

Please tend your N«une and AiJdmi < »c would be grateful fur 
S 65 ctih or samps for postage, bui run required t eg: 

INTERCON Data Systems 

Dept. l t P.O. Bo* 696 
G<imbHlls, MD 2 1054-0696 




I 



AMATEUR RADIO STATION 

LOGBOOK 



a 



USDOS 1^ V U D W U r\ 124 95 

Written by KI6L0 

A multT-taatur* lag^lrt^ application for PC/XT/AT a 
compatibles. Fait, ueer friendly operation feature* 
on -line HELP levy* multiple logs - selectable vnNe 
n the program. Display beam headings and 0X info 
using a "HGTKEV whir* ltlll logging. Callsign duping 
during Input and very fast data retrieval, Print cmrom 
log reports: prefix t country, continent and ion* lists; 
QSUqrd lahflk from data In dBASE 3-1- compatible 
database flies. Custom backup feature allows auto- 
matic backups and restores of log database tll#f. 
Complete with 50 page manual (on— disk), 

US-DOS &xx with 51 2k RAM - No coprocessor required. 

Hard disk recommended. Selectable printer drWwtw 
Uses COLOR or MONOCHROME graphics. 

Send $24.95 check or M.O. Add $5 for COD (US * 
Canada only). CA residents add $1.50. Specify 5.23" 
(360k) or 3.5" (720k) disk. 



LEB E/tterprises 
(619) 446-4355 



1127N IuPnu 
CA 93555 USA 



CIRCLE 2 ON READER SERVICE CARD 



INTRODUCING 
THE NEW lO-Hz-1.4 GHz 



DATASCAN ) FREQUENCY COUNTER 

from B & B INSTRUMENTS 



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* You can use it to check disc drives, VTR's, TV's, HTs or tune your HF rig to meet a 
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* The C 1400 also comes with a built-in 18 d8 prearnp for increased sensitivity. You 
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mom 



C900 



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ALL UNITS ARE COVERED BY OUR S YEAR LIMITED WARRANTY 

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TERMS: Shipping, handling and insurance 
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add 6% sales tax. 



* Batteries not included 



manufactured by 

B & B INSTRUMENTS 

408 La Cresta Hgts Road 

EICajon,CA92021 




800-882-1343 






Llkt 


JUN'i 


IC-781 Mew Deluxe HF Rig 


££149 


Call? 


lC-765Gsn. CvgXcvF 


314995 


CallS 


IC-735Gen.CvgXcvr 


1149 


CallS 


lC-751AGen,CvgXcvr 


1699 


CftllS 


IC-R7000 25- 1 300 MHz Rcvi 


1199 


Ca)IS 


IC-R71 A 100 kHz-30 MHz Rcvr 




Call S 


IC-22BA/H FM Mobile 2S#/45w 


509/539 


CaiS 


IC-28A/H FM Mobile 25w/4S* 


469J499 


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IC-2GAT 2i* 7w HT 


429 95 


Cat* 


IC-900Sik Sand Motnte 


639 


CaflS 


IC-3SATS20MH2- 


449 


CalS 


IC-2SAT2M 


439 


Cans 


C-4SAT 


449 


CalS 


IC-4SA FH Motwl* 2S* 


509 


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1G4GATr4ew6*HT 


449 95 


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IC-3aA?SwFWXcvr 


489 


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629 96 


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IC-04AT 



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$473.15 

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SALE 

$333.05 
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KENWOOD 



HZ-i Wideband Hew 


599 96 


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TS-940S/AT Gen Cwg Xcw 


2449 95 


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1999 95 


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1059 95 


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TB-751 A ai Mode Mobee 25m 


609 95 


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TM-231 A 2m 45* 


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TH-75A 2m/70cm HT 


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TM-431 A Com pact F M 35 w 


699 95 


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TH-45AT Sw Pocket HT 220 MHz 


369.95 


CallS 



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220/440 DUAL BAND 



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FT-7B7GXGen Cvg Xcvr 


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3919 Sepulveda Blvd. 

Culver City, CA 90230 
213-390-8003 



CIRCLE 272 OH flEAOEft SERVICE CARD 



Number 34 on your Feedback card 




ARTER 'N' BUY 



QSLs TO ORDER. Variety of styles, 
colors, card stock. W4BPD QSLs, PO 
Drawer DX. Cordova SC 29039. 

BNB26Q 

THE DX'ERS MAGAZINE Up-to-date, 
informative, interesting. Compiled and 
edited by Gus Browning W4BPD, DX- 
CC Honor Roll Certificate 2-4, Send 
for free sample and subscription infor- 
mation today. PO Drawer DX, Cordova 
SC 29039. 6NB261 

AZDEN SERVICE by former factory 
technician. Fast turnaround. PCS-300 
NiCads $36.95. Southern Technolo- 
gies Amateur Radio, Inc., 10715 SW 
190 St ffl. Miami FL 33157, (305) 238^ 
3327, BNB262 

QSL CARDS— Look good with top 
quality printing. Choose standard de- 
signs or fully customized cards, Better 
cards mean more returns to you. Free 
brochure, samples. Stamps appreciat- 
ed, Chester QSLs, Dept A, 310 Com- 
mercial, Emporia KS 66801 . BIMB434 

SUPERFAST MORSE CODE SU- 
PEREASY, Subliminal cassette, $10. 
LEARN MORSE CODE IN 1 HOUR. 
Amazing new supereasy technique. 
$10. Both $17. Money back guarantee, 
Free catalog; SASE Bahr, Dept 73-1 , 
1196 Citrus. Palmbay FL 32905. 

BNB531 

SB-22G/221 OWNERS: 17 detailed 
mods which include 1 60-6 meter oper- 
ation, QSK, + enhanced p.s. 50% re- 
bate for new mods submitted! 9 pages 
of 3-5002 tech info. $11 postpaid.— In- 
fo. SASE, BOB KOZLAREK WA2SQQ, 
69 Memorial Place. Etmwood Park NJ 
07407. BNB581 

ELECTRONIC KITS & ASSEMBLIES. 

For our latest catalog, SASE (45c) to: 
A&A Engineering, 2521 W. LaPalma, 
#K, Anaheim CA 92801 . BNB624 



r 



HT -CLONE BATTERIES: ICOM: BP- 
38 Double BP3 "Wall Chargeable" 
$43.95, BP5 $42.95, YAESU: FNB2 
$21.95, SANTEC: 142^442/1200 (3 
Pin) $22,95, "REBUILDING: SEND- 
UR-PACK" loom BP3 $20, BP5 $28 T 
BP7/8S34, BP70$30. Yaesu FNB4/4A 
$37, Kenwood PB21 $18, PB25/H/26 
$28, T-T2991 $28. "U DO-IT REPAIR 
INSERTS" ICOM; BP2 $18.95, BP3 
$16.95, BP5S22.95, BP7/BP8 $28,95, 
KENWOOD: PB21 $12.95, PB24/25/ 
26 $19.95. AZDEN 300 $19 95 T YAE- 
SU: FNB4/4A $32.95, TEMPO: 
51,2.4,5,15/450 $22.95, 12V/5Ahr 
PORTA-PAC W/CHGR $49.95, ' 'AN- 
TENNAS^" 2MTR 5/8-Tel/BNC $14.95. 
'TELEPHONE / PAGER & COMMER- 
CIAL PACKS" "FREE CATALOG/' $3 
Shipping/order. PA +6%, Visa-M/C 
+ $2. (814) 623-7000, CUNARD AS- 
SOCIATES, Dept. 7, R.D. 6 Box 104, 
Bedford PA 1 5522- BN B628 

ROSS 1 $$$$ NEW October SPE- 
CIALS: KENWOOD TS-44QS/WAT 
$1219.90, TR-8400 $379.90, TM-231A 
$389.90, TM-401B $307,99, TM-411A 
$339.99, TS-71 1 A $839.90, TW-4100A 
$45999, SM-220 $409.90; MIRAGE C- 
301 2R $329.99, B-23S $93.90, B1016 
$249.90, B108 $145 90; ICOM IC- 
12AT $369.90, IC-1200 $544.99, IC- 
32AT $539 90 r IC^725 $809.90, fC- 
3200 $464.99; YAESU FT-747GX 
$709,90, FT-726R $799.90, FT-470 
$465.90, YR-901 $549.99, SC-1 
$1 48.99, FT-41 1 $326.90; 
CUSHCRAFT AV4 $85. 90, AP-8 
$159.90, A~3 $259.90, 220-QK 
$229,90; AEA PK-64A/WHFM 
$189.99, ALL LXO, (LIMITED TIME 
OFFER) LOOKING FOR SOMETHING 
NOT LISTED?? CALL OR WRITE. 
Over 8780 ham-related items in stock 
for immediate shipment. Mention ad. 
Prices cash, F.O.B, PRESTON. 
HOURS TUESDAY-FRIDAY 9:00 TO 
6:00, 9:00-2:00 P.M. MONDAYS. 
CLOSED SATURDAY & SUNDAY. 



1 



Barter 'N' Buy advertising must pertain to ham radio products or services. 

D Individual {noncommercial) »*••♦♦»#»• 5QC per word 

□Commercial $1 .50 per word 

Prepayment required. Count only the words in the text. Your address is 
free. 73 cannot verify advertising claims and cannot be held responsible 
for claims made by the advertiser. Liability will be limited to making any 
necessary corrections in the next available issue. Please print clearly or 
type (double-spaced). 



No discounts or commissions are available. Copy must be received in 
Peterborough by the first of the second month preceding the cover date. 
Make checks payabfe to 73 Magazine and send to; Donna DiRusso, Barter 
N' Buy, Box 278, Forest Road, Hancock, NH 03449. 

102 73 Amateur Radio • October, 1989 



ROSS DISTRIBUTING COMPANY, 78 
SOUTH STATE, PRESTON ID 83263. 
(208) 852-0830. BN6654 

WRITTEN EXAMS SUPEREASY, 
Memory aids from psychologist/engi- 
neer cut studytime 50%. Novice, Tech, 
Gen: $7 each- Advanced, Extra: $12 
each. Moneyback guarantee. Bahr, 
Dept 73-1, 1196 Citrus, Palmbay FL 
32905. BNB691 

ROSS $$$$ USED October 
SPECIALS: KENWOOD TS-930S/ 
WAT.YG-455C1 $1459,90, SP-620 
$69,90, R-300 $189.90, TM-231A 
$339.90; ICOM PS-1S $122.90, IC- 
720A $599.90. IC-725W/FL-1 01 
$769.90; YAESU FT-ONE $1199.90, 
FRA-77O0 $39.90, FRT-7700 $45.50, 
FTV-707W/70CM MODULE $26990; 
COLLINS KWM-2 $499. 90, 312B4 
$259.90, KWM-3B0 3 FILTERS NB,SP. 
$1995.90, 75S-1 & 32-S1 $425.00. 
LOOKING FOR SOMETHING NOT 
LISTED?? CALL OR WRITE, WE 
HAVE OVER 235 USED ITEMS in 
stock, MENTION AD Prices cash, 
F.O.B. PRESTON. HOURS TUES- 
DAY-FRIDAY 9:00 TO 6:00, 9:00-2:00 
P.M. MONDAYS. CLOSED SATUR- 
DAY & SUNDAY. ROSS DISTRIBUT- 
ING COMPANY, 78 SOUTH STATE. 
PRESTON ID 83263. (208) 852- 
0830. BNB709 

$50 PACKET DIGICOM >64— A fan- 
tastic software based PACKET system 
for the Commodore 64. Order KIT #1 54 
for $49.95 or Assembly #154 for 
$79,95. both include FREE DISC. Add 
$3.50 s/h. A & A Engineering, 2521 W, 
LaPalma, #K, Anaheim CA 92801. 
(71 4) 952-21 1 4. MC or VISA accepted. 
BNB732 

HAM TRADER YELLOW SHEETS. In 
our 28th year. Buy, Swap, Sell ham 
radio gear. Published twice a month. 
Ads quickly circulate, no long wait for 
results. Send business size SASE for 
sample copy, $15 for one year (24 is- 
sues). P.O.B. 2057, Glen Ellyn IL 
60138-2057 or P,O.B, 15142, Seattle 
WA9811S, BN8741 

$$$$$ SUPER SAVINGS $$$$$ on 
electronic parts, components, sup- 
plies, and computer accessories. Send 
one dollar for 1 -year subscription to our 
40-page catalogs and their supple- 
ments. Get on our mailing list. BCD 
ELECTRO, PO Box 450207, Garland 
TX 75045 or call {214} 343-1770, 

BNB749 

HAM RADIO REPAIR all makes, mod- 
els. Experienced, reliable service. 
Robert Hall Electronics, Box 280363, 
San Francisco CA 94128-0363. (408) 
729-8200. BNB751 

WANTED: Ham Equipment and other 
property. The Radio Club of Junior 
High School 22 NYC, mc„ is a nonprof- 
it organization, granted 501(C)(3) 
status by the IRS, incorporated with 
the goal of using the theme of ham 
radio to further and enhance the edu- 
cation of young people nationwide. 



Your property donation or financial 
support would be greatly appreciated 
and acknowledged with a receipt for 
your tax deductible contribution. Meet 
us in person at the Lima, Ohio, Ham- 
fest, October 15, and learn all about 
the most exciting and beneficial appli- 
cation of ham radio today. P lease write 
us at: PO Box 1052, New York NY 
10002. Round the clock Hotline: (516) 
674-4072. Thank youl BNB762 

INDIVIDUAL PHOTOFACT FOLD- 
ERS. #10 to #1400, $4.00. #1401 up, 
$6,00. Sam's books, $7,00, Postpaid. 
Allen Loeb, 414 Chestnut Lane, East 
Meadow NY 1 1 554. BNB766 

AVANTEK ATF10135 $12-00. 
MMICs, PC. board, SASE: WA31 AC, 
7148 Montague St., Philadelphia PA 
19135. BNB771 

HAMLOG COMPUTER PROGRAM 
Full features, 17 modules, Auto^logs, 
7-band WAS/DXCC. Apple $19.95. 
IBM, CP/M, KAYPRO, TANDY, CR8 
$24.95. 73-KA1AWH, PB 2015, Pea- 
body MA 01 960. BNB775 

WE DID IT!!!! At East a BETTER 
MOUSE TRAP. Quick, Easy, and Sinrv 
pie— Study Cards covering Novice- 
Tech— General— Advanced — and Ex- 
tra All questions— answers— and 
drawings at your fingertips. Key words 
underlined— no fighting for computer 
time and panic attacks trying to read 
books. Custom-made for the lady of the 
house by ONE. SUPER EASY TO 
USE. Successful users— ages 8 to 
76— you can do it TOO!!!! Write Car- 
olyn N5MUU, PO Box 16646, Hatties- 
burg MS 39402, BNB792 

WANT TO GET TO KNOW THE LAT- 
EST FCC news, operating tips, tech 
talk, free ads? Get America's #1 club 
publication monthly, lowest dues fig- 
ure in US for 61 services and benefits. 
Join the Triple States Radio Amateur 
Club. Send $3,50 tor six months to: 
TSRAC, Box 240, RD 1 \ Dept, 73, Ade- 
na OH 43901. BNB812 

1050+ DX AWARDS, 103 countries 
detailed in KlBVs Directory. $15,65, 
Ted Melinosky, 525 Foster St., South 
Windsor CT 06074-2936. BNB835 

100 QSL CARDS $8! Shipped post- 
paid. Free samples. Shell Printing, 
KD9KW, PO Box 50A, Rockton IL 
61072. BNB859 

RECEIVING TUBES; $2.00 each, plus 
shipping, while they last. Octals, loc- 
tals, seven and nine pin. Tested before 
shipping, Guaranteed good. Electronic 
Stockroom Inc., 346 Columbia Turn- 
pike, Rensselaer NY 1 2144. Calf: (518) 
477-2381 . BNB865 

CURRY COMMUNICATIONS proudly 
introduces a complete line of easy to 
build kits for L,F, and 1750 meters. 
Please write for brochure. Curry Com- 
munications. 852 North Lima Street, 
Burbank CA 91 505. BN B874 



WANTED: Alt types of Electron Tubes. 
Call loJt lree 1 (800)421-9397 or 1 (612) 
429-9397. C 4 N Electronics. Harold 
Bramstedf. 6104 Egg Lake Road. 
Hugo MN 55036. BNB976 

RtT KITS for most transceivers. £15- 
Info only, send SASE, Loren Wail en 
KA7AZM, 6323 S.W. 100th. Tacoma 
W A 98499. BNB885 

YAGI BUILDERS, 6061 -T6 tube traps. 
Good for 1500 PEP. SASE for details. 
No collect calls. Brown Engineering, 
Inc., 5501 SW 25lh Court Hollywood 
FL 33023. (305) 989-4658- BNB88B 

LOW COST HAM GEAR. SASE for 
free list. WA4DSO. 3037 Audrey Or, 
Gaslorna NC 28054. BNB09O 

SURPLUS CATALOG. 72 pages 52. 
Surplus, PO Box 276, Afburg VT 
05440. BNB891 

WANTED: MILITARY SURPLUS VHF/ 
UHF SOLID STATE RADIO EQUIP- 
MENT, WE NEED AFKM64, ARC- 
114A f ARC-116, ARC- 150, ARC- 159, 
ARC-182, ARC-186. TOP DOLLAR 
PAID OR TRADE FOR NEW AMA- 
TEUR GEAR WRITE^PHONE BILL 
SLEP (704) 524-7519, SLEP ELEC- 
TRONICS COMPANY, HtGHWAY 
441 , OTTO NC 28763. BNB892 

BIRD ELEMENTS, WATTMETERS. 
DUMMY LOADS— Buy and Sell. {609} 
227-5269. Eagle. 100 Dearoorne Ave. 
Bfack wood NJ 0801 2. BN B894 

2-WAY RADIO SYSTEM. Used VHF 
base stations, remotes, portable ra- 
dios. UHF car radios + many extras. 
Call Chris, (202) 944-2802 for equip- 
ment * price list. BNB897 

MAKE YOUR OWN REPEATERS Mo- 
torola Micor Radios 45 watt, 4 treq, 
136-T50 MH2 $80.00. Motorola Micor 
Radios 45 watt, 8 freq, 136-150 MHz 
S 120 00 Motorola Motracs Radios 25 
MHz S32 00. Micor Access Groups 4 
freq Scan Head, spkr., mic. cable 
$75.00. Mtcor Access Groups 8 freq. 
Scan Head. spkr,. mic, cabte $1 00.00. 
GE Exec 11's Radio 45 watt. 1 freq. 
136-150 MHz $100 with ail acces- 
sories $200,00, GE Exec 1 1 Radio 50 
watt, 42-50 MHz $10000 with all ac- 
cessories $200.00. EM~2 DTMF mics 
wilh Micor, Mftreks, Syntor Plugs, hard 
wire changeable with schematic 
$20 00. DTMF Encoders with lite, 
choice of Plug Micor or Master II 
$30,00 each. LAMBDA Power Sup- 
plies LNS-P-12* 120 volts. 12 volt DC 
14 Amp. $100. Wolfe Commumca* 
lions, 1113 Central Ave., Billings MT 
59102 (406)252-9220. SNB900 

CIRCUIT BOARDS— for your Home- 
brew Projects- Can war* from your 
schematic or from your idea. Design 
Layout Sen/ice or Fabrication Service 
You don't pay until you're satisfied, 
2781 Shaffer Ave,, Cincinnati OH 
45211, BNB901 



WW5B DOES IT AGAIN! Send SASE 
for list of surplus Hewlet-Packard UHF, 
H-P audio oscillators, H-P distortion 
meters, H*P frequency meters, power 
supplies, power conditioning equip- 
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WW5B. PO Box 460, Brookshire TX 
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CW IDENTIFIER: 700 Hz Sinewave, 
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Dallas TX 75230-3429. (214) 891- 
0509. BNB905 

WANTED: Clean, operable Icom 255A 
or260A, A. Campo. 816 W. Knapp St . 
Rice Lake Wl 54868. BNB906 

HAM SOFTWARE and other "share- 
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catalog. JK&S, Depi. 73, POB 50521. 
Indianapolis IN 46250-0521 . BNB907 

DIGITAL AUTOMATIC DISPLAYS. 

Be specific. 45c SASE. GRAND SYS- 
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WA 98230. BN8908 

HAMSOFT— Public Domain Soft- 
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COMMODORE/AMIGA CHIPS, 
PARTS, REPAIRS, Call for lowest 
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C64— $27.95 (plus UPS); New Amiga/ 
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Commodore "Pet" Computers, "AS 
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Parts, "AS IS'*— $29,95, The "Diag- 
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C64/1541 Drive— $7.95, ., VISA/ 
MC.-Q.E.P, Co,. Inc.. Kasara Mi- 
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1 0980. (BOO) 248-2983 BNB9 1 

HAM SOFTWARE IBM/Compatibles 
10 disks $2695. MCA/lS A/Discover 
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TX 76248-0014 (817) 498^1242. 

BNB91 1 

HOMEBREW PROJECTS LISTS 

SASE WB2EUF. Box 708. East Hamp- 
ton NY 11937. BNB912 

ELECTRON TUBES: All types & sizes. 
Transmitting, Receiving, Micro- 
wave. , Large inventory = same day 
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Compton CA 90224. (80OJ 346- 
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*COM T KENWOOD & YAESU OWN- 
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RC, ($12.50) Canada ($13.00) Else- 
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Number 35 on your Feedback card 



ROPA GA TION 



by Jim Gray W1XU 
PO Box 1079 
PaysonAZ 85541 

October Activity 

This month wiN find excellent 
HF propagation on alt of the HF 
bands between 40 and 10 meters, 
and even 60 meters will begin to 
look a bit lively. The first week of 
the month will exhibit variable 
conditions ranging from good to 
poor, while the second 
week of the month is likely 
to be the worst 

Both electromagnetic 
and geologic conditions 
will bring surprises — most 
of them unwanted. The 
third and fourth weeks of 
the month will present a 
vast improvement, down to 
and including the last days 
of the month, but due to 
days of excessive ioniza- 
tion, high absorption can 
still occur and deep fading 
may prevail on the DX 
bands. Six meters will be 
ac!ive t as will 10 on up, as 
Old Sol races to an early 
peak of Cycle 22. possibly 
in mid to late 1990. Make 
the most of your DX oppor- 
tunities this month, as 
many will exist. Keep an 
eye on developments via 
WWV at 18 minutes past 
each hour, and of course, 
through the charts provid- 
ed in 73. 



Jim Gray W1XU 



onsets of poor or good conditions 
may vary by as much as a day or 
two, due primarily to the increas- 
ingly unpredictable nature of the 
sun at times of high soiar activity. 
Strong sunspot groups can pro- 
duce flares and sudden iono- 
spheric disturbances that may 
even create HF communications 
"blackouts' 1 for several hours at a 
time on the days marked "P." 



Get Ready for DXing 

Use the MUF chart for 
bands and countries, but 
use the calendar for daily 
summaries of conditions. 
Bear in mind that specific 

























n 


EASTERN UNITED STATES TO: 


GMT TO ^ W 06 0B 10 12 U 16 *■ 20 22 


ALASKA 


t5"J50:20 = 2Qi^ 


— 


:_ 


— 




_ 




IS* 


ARGENTINA 


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15 


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to 


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_ _ _ _ 


CENTRAL UNITED STATES TO: 


i ALASKA 10 15. [20 2D X 


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wmm 


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WESTERN UNITED STATES TO: 


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20 20 20 


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HI 



OCTOBER 1989 

SUN MON TUE WED THU FRl SAT 


1 

P-F 


2 

F-G 


3 

G 


4 

G-F 


5 

F 


6 

F-P 


7 
p 


8 
p 


9 

p 


10 

p 


11 

P 


12 

p 


13 
p 


14 

p 


15 

p 


16 

F 


17 

P-F 


18 

F 


19 

F-G 


20 

G 


21 

G 


22 

G 


G-F 


24 

F 


25 

F-G 


26 

F 


27 


28 

F 


29 

F-G 


30 

G 


31 

G-F 











73 Amateur Radio • October, 1989 103 



Others May Try to Imitate, But... 



• 



• 




Advanced Electronic ApoUcaiicms tnc 



Model P! 



THRESHOLD M 



DCD 






TUNE 



PAKRATT 232 



MULT 



L t i 



NO tFC 0*6H 



DON OMt) 



STATUS 



MODE 



Morse Code - Baudot - ASCII - AMTOR - Packet - Facsimile - Navtex 



It's a lesson you learn very early in life. Many can be good, some may be better, but only one can be 
the best. The PK-232 is the best multi-mode data controller you can buy* 



i 




The PK-232 should be listed in 
the amateur radio dictionary* under 
the word Versatile. One data con- 
troller thai can receive seven digital 
modes, and can be used with almost 
every computer or data terminal. 
You can even monitor Navtex, the 
new marine weather and navigation- 
al system. Don't forget two radio 
ports for both VHF and HE and a no 
compromise VHF/HF/CW internal 
modem with an eight pole bandpass 
filter followed by a limiter dis- 
criminator with automatic threshold 
control. 

The internal decoding program 
tSIAM feature can even identify 
different types of signals for you, in- 
cluding some simple types of RTTY 
encryption. The only software your 
computer needs is a terminal pro- 
gram. 





PC Pakratt Packet TX/RX Display 



Facsimile Screen Display 

2 Software Support 

While you can use most modem 
or communications programs with 
the PK-232, AEA has two very spe- 
cial packages available exclusively 
for the PK-232....PC Pakratt with 
Fax tor IBM PC and compatible 
computers, and Com Pakratt with 
Fax for the Commodore 64 and 1 28. 

Each package includes a terminal 
program with split screen display, 
QSO buffer, disk storage of received 
data, and printer operation, and a 
second program for transmis- 
sion/reception and screen display of 
facsimile signals. The IBM 
programs are on 5 1/4" disk and the 
Commodore programs are plug-in 
ROM cartridges* 



3 Proven Winner 

No matter what computer or ter- 
minal you plan to use, the PK-232 is 
the best choice for a multi-mode 
data controller. Over 20,000 
amateurs around the world have on- 
air tested the PK-232 for you. They, 
along with most major U,S, amateur 
magazines, have reviewed the PK- 
232 and found it to be a good value 
and excellent addition to the ham 
station. 

No other multi-mode controller 
offers the features and performance 
of the PK-232. Don't be fooled by 
imitations. Ask your friends, or call 
the local amateur radio store. We're 
confident the PK-232 reputation will 
convince you that it's (ime to order 
your very own PK-232. 

Call an authorized AEA dealer 
today. You deserve the best you can 
buy, you deserve the PK- 232. 



Advanced Electronic 
Applications, Inc. 

RCXBoxC-2160 
Lynnwood, WA 98036 

206-775-7373 

AEA Retail $415.95 

Amateur Net $349.95 



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J- 










. . . pacesetter in Amateur Radio 









46 



TS-440S 



DX-citing! " 



Compact high performance HF transceiver 
with general coverage receiver 



Kenwood's advanced digital know-how 
brings Amateurs world-wide "big-rig" 
performance in a compact package. We 
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feeling you get every time you turn the 
power on! 

• Covers All Amateur bands 
General coverage receiver tunes from 
100 kHz -30 MHz, Easily modified for 
HF MARS operation 

• Direct keyboard entry of frequency 

• All modes built-in 

USB, LSB, CW AM. FM, and AFSK> Mode 
selection is verified In Morse Code, 

• VS-1 voice synthesizer (optional) 



• Superior receiver dynamic range 
Kenwood DynaMix" Ngh sensitivity direct 
mixing system ensures true 102 dB receiver 
dynamic range. (500 Hz bandwidth on 20 m} 

• 100% duty cycle transmitter 

Super efficient cooling permits continuous 
key-down for periods exceeding one hour 
RF input power is rated at 200 W PEP on 
SSB. 200 W DC on CW T AFSK. FM, and 110 
W DC AM, (The PS-50 power supply is 
needed for continuous duty.) 

• Built-in automatic antenna tuner 
(optional). Covers 80-10 meters. 

• 5 IF filter functions 

• VOX, full or semi break-in CW 



• Dual SSB IF filtering 

A buitt-in SSB filter is standard. When an 
optional SSB filter (YK-683 or YK-88SN) is 
installed, dual filtering is provided, 

• AMTOR compatible 

• Adjustable dial torque 

• 100 memory channels 
Frequency and mode may be stored in 
10 groups of 10 channels each. Split fre- 
quencies may be stored in 10 channels 
for repeater operation. 

• TU-8 CTCSS unit (optional) 

• Superb interference reduction 

IF shift tuneable notch filter, noise blanker. 
all-mode squetch. RF attenuator, RfT/XIT, 
and optional fitters fight QRM 

• MC-43S UP/DOWN mic. included 

• Computer Interface port 




Optional accessor!*? 

m AT- 440 inter rial auto antenna tuner (80 m - 10 rn} 

* AT-250 external auto tuner (160 - 10 m» 

• AT-t30 compact mobile antenna tuner (160 m - 



88SN 24 KH2/18 kHz SSB filters • MC-60A/80/85 
desk microphones * MC-55 (8P) mobile micro- 
phone * HS-46/6/7 headphones * SP-4V5CW50 



Kenwood 
takes you from 
HF to OSCAR! 





10 m) • If -232C/1C-1G level translator and modem 
IC kit * PS-50 heavy duty power supply * PS-430/ 
PS-3D DC power supply * SP-430 external 

speaker * MB-43G mobile mounting bracket 

• YK-88C/88CN 500 Hz/270 Hz CWfilters * YK-88S- 



mobrte speakers • MA-5/VP-1 HF 5 band mobile 
helical antenna and bumper mount » 1V922A 

2 kw PEP linear amplifier « 5M-220 slation monitor 

(no pan display) * VS-1 voice synthesizer 

• TU-fl CTCSS tone unit • PG-2C extra DC cable. 



Complete service manuals are available tor aft Kenwood transceivers and mo$t accessories 
Specifications and prices are syfl/eel ro change wrthout no* »ce Of obligation 



KENWOOD 

KENWOOD USA. CORPORATION 

COMMUNICATIONS &TEST EQUIPMENT GROUP 

P.O.BOX 22745, 2201 E. Dominguez Street 
Long Beach, CA 90801-5745 

KENWOOD ELECTRONICS CANADA INC. 

P.O. BOX 1075, 959 Gana Court 
Mississauga. Ontario, Canada L4T 4C2